(RNS) Religiosity is on the decline in the U.S. and atheism is on the rise, according to a new worldwide poll.

The poll, called "The Global Index of Religiosity and Atheism," found that the number of Americans who say they are "religious" dropped from 73 percent in 2005 (the last time the poll was conducted) to 60 percent.

At the same time, the number of Americans who say they are atheists rose, from 1 percent to 5 percent.

The poll was conducted by WIN-Gallup International and is based on interviews with 50,000 people from 57 countries and five continents. Participants were asked, "Irrespective of whether you attend a place of worship or not, would you say you are a religious person, not a religious person, or a convinced atheist?"

The seven years between the polls is notable because 2005 saw the publication of "The End of Faith" by Sam Harris, the first in a wave of best-selling books on atheism by Christopher Hitchens, Richard Dawkins, Daniel Dennett and other so-called "New Atheists."

"The obvious implication is that this is a manifestation of the New Atheism movement," said Ryan Cragun, a University of Tampa sociologist of religion who studies American and global atheism.

Still, Cragun does not believe the poll shows more people are becoming atheists, but rather that more people are willing to identify as atheists.

"For a very long time, religiosity has been a central characteristic of the American identity," he said. "But what this suggests is that is changing and people are feeling less inclined to identify as religious to comply with what it means to be a good person in the U.S."

Another possible factor may be the number of atheists within organized efforts by American atheist groups to encourage those who do not believe in God to say so publicly. The Out Campaign, a project of the Richard Dawkins Foundation for Reason and Science, was launched in 2007 and has since been endorsed by several national atheist groups.

The current poll confirms a declining religiosity -- both at home and abroad -- that's been detected in other polls. The 2008 American Religious Identification Survey found that 15 percent of Americans said they have no religion -- different from being a "confirmed atheist," but nonetheless up from 8 percent in 1990.

Barry Kosmin, the principal investigator for the ARIS report, said he's skeptical of the new study.

"The U.S. trends are what we have found and would expect, but the actual numbers are peculiar to say the least," he said. "The drops in religiosity seem too sharp for the time period -- people just don't change their beliefs that quickly. Most of the trend away from religion has demographic causes and demography moves 'glacially.'"

Specifically, he points to the poll's finding that Vietnam, while showing a sharp 23 percent drop in religiosity since 2005, also shows no atheists. "Eight million Communist Party members but zero atheists?" he said. "That statistic makes me very doubtful of the accuracy of the survey overall and some of the international comparisons."

Other findings from the poll include:

  • Besides Vietnam, Ireland had the greatest change in religiosity, down from 69 percent to 47 percent.

  • China has the most "convinced atheists," at 47 percent, followed by Japan (31 percent), Czech Republic (30 percent) and France (29 percent)

  • The most religious countries are in Africa (Ghana, Nigeria, Kenya), South America (Brazil, Peru) and Eastern Europe (Macedonia, Romania, Armenia).

  • Countries with the same percentage of atheists as the U.S. are Poland, Moldova and Saudi Arabia.

Click through the slideshow to view most and least religious cities in the United States

Loading Slideshow...
  • Salt Lake City, UT

    73,487 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/c/c7/Temple_Square_October_05_%288%29_c.JPG" target="_hplink">here</a>.

  • Birmingham, AL

    Metro area Birmingham-Hoover, AL<br> 70,990 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/2/26/16th_Street_Baptist_Church.JPG" target="_hplink">here</a>.

  • Oklahoma City, OK

    60,249 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/4/44/Bricktown_Canal_Water_Taxis_in_Oklahoma_City.jpg" target="_hplink">here</a>.

  • Memphis, TN-MS-AR

    Metro area: Memphis, TN-MS-AR<br> 58,847 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/8/8c/Hernando_de_Soto_Bridge_Memphis.jpg" target="_hplink">here</a>.

  • Pittsburgh, PA

    57,695 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/2/2f/Pittsburgh_WEO_Night_1.jpg" target="_hplink">here</a>.

  • Chicago, IL-IN-WI

    Metro area: Chicago-Joliet-Naperville, IL-IN-WI<br> 57,162 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/4/4b/2011-08-07_2000x3000_chicago_from_skydeck.jpg" target="_hplink">here</a>.

  • Providence, RI-MA

    Metro area: Providence-New Bedford-Fall River, RI-MA<br> 56,840 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/7/70/Providence_Cathedral%2C_RI_edited.JPG" target="_hplink">here</a>.

  • Boston, MA-NH

    Metro area: Boston-Cambridge-Quincy, MA-NH<br> 56,765 religious adherents per 100,000 persons.<br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/3/3e/USA_09562_Boston_Luca_Galuzzi_2007.jpg" target="_hplink">here</a>.

  • New York, NY-NJ-PA

    Metro area: New York-Northern New Jersey-Long Island, NY-NJ-PA<br> 55,595 religious adherents per 100,000 persons. <br> (Photo: In this March 26, 2012, file photo, One World Trade Center towers above the Lower Manhattan skyline and Hudson River in New York. One World Trade Center, the giant monolith being built to replace the twin towers destroyed in the Sept. 11 attacks, will lay claim to the title of New York City.)

  • Dallas, TX

    Metro area: Dallas-Fort Worth-Arlington, TX<br> 55,536 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/1/17/The_Catholic_Cathedral_of_Santuario_de_Guadalupe_in_the_Downtown_Dallas_Arts_District%2C_10-26-10.jpg" target="_hplink">here</a>.

  • Houston, TX

    Metro area: Houston-Sugar Land-Baytown, TX<br> 55,144 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/e/e2/Aerial_view_of_Texas_Medical_Center.jpg" target="_hplink">here</a>.

  • Buffalo, NY

    Meto area: Buffalo-Niagara Falls, NY<br> 54,706 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/e/e7/20080310_Soldiers_and_Sailors_edit.JPG" target="_hplink">here</a>.

  • Philadelphia, PA-NJ-DE-MD

    Metro area: Philadelphia-Camden-Wilmington, PA-NJ-DE-MD<br> 54,668 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/3/39/Independence_Hall.jpg" target="_hplink">here</a>.

  • San Antonio, TX

    Metro area: San Antonio-New Braunfels, TX<br> 54,093 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/en/1/11/Rio_del_pasio_05.jpg" target="_hplink">here</a>.

  • New Orleans, LA

    Metro area: New Orleans-Metairie-Kenner, LA<br> 53,479 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/e/ef/Altaner.jpg" target="_hplink">here</a>.

  • Minneapolis, MN-WI

    Metro area: Minneapolis-St. Paul-Bloomington, MN-WI<br> 52,061 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/8/84/Minneapolis_05042012.jpg" target="_hplink">here</a>.

  • Milwaukee, WI

    Metro area: Milwaukee-Waukesha-West Alis, WI<br> 51,823 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/d/d5/St_Stanislaus_Catholic_Church.jpg" target="_hplink">here</a>.

  • Charlotte, NC-SC

    Metro area: Charlotte-Gastonia-Rock Hill, NC-SC<br> 51,764 religious adherents per 100,000 persons. <br> Photo credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/3/3b/Southpark_aerial_Charlotte_NC.jpg" target="_hplink">here</a>.

  • Los Angeles, CA

    Los Angeles-Long Beach-Santa Ana, CA<br> 51,382 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/9/92/Hollywood_boulevard_from_kodak_theatre.jpg" target="_hplink">here</a>.

  • Cleveland, OH

    Metro area: Cleveland-Elyria-Mentor, OH<br> 51,185 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/5/56/StTheodosius.jpg" target="_hplink">here</a>.

  • Nashville, TN

    Metro area: Nashville-Davidson-Murfreesboro-Franklin, TN<br> 50,694 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/9/94/Nashville_Downtown.JPG" target="_hplink">here</a>.

  • Louisville, KY-IN

    Metro area: Louisville-Jefferson County, KY-IN<br> 50,445 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/1/19/Cathedral_Assumption_Louisville.jpg" target="_hplink">here</a>.

  • Richmond, VA

    50,113 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/3/3f/Cathedral_of_the_sacred_heart_.JPG" target="_hplink">here</a>.

  • Jacksonville, Florida

    50,093 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/9/9d/ChurchJax1.jpg" target="_hplink">here</a>.

  • Atlanta, GA

    Metro area: Atlanta-Sandy Springs-Marietta, GA<br> 49,721 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/7/76/Shrine_of_the_Immaculate_Conception.jpg" target="_hplink">here</a>.

  • Kansas City, MO-KS

    49,702 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/d/d2/Community_Christian_Church_KCMO.jpg" target="_hplink">here</a>.

  • St. Louis, MO-IL

    48,889 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/5/5a/Tower_Grove_Park_Scene_1.jpg" target="_hplink">here</a>.

  • Hartford, CT

    Metro area: Hartford-West Hartford-East Hartford, CT<br> 47,226 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/6/64/Cathedral_of_Saint_Joseph_in_Hartford_3%2C_2009-09-02.jpg" target="_hplink">here</a>.

  • Cincinnati, OH-KY-IN

    Metro area: Cincinnati-Middletown, OH-KY-IN<br> 44,672 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/3/30/Cincinnati_oh_skyline.jpg" target="_hplink">here</a>.

  • Detroit, MI

    Metro area: Detroit-Warren-Livonia, MI<br> 44,583 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/2/23/Ste_Anne_de_Detroit.jpg" target="_hplink">here</a>.

  • Washington, DC-VA-MD-WV

    Metro area: Washington-Arlington-Alexandria, DC-VA-MD-WV<br> 44,576 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/e/ef/Cherry_Blossoms_and_Washington_Monument.jpg" target="_hplink">here</a>.

  • Raleigh, NC

    Metro area: Raleigh-Cary, NC<br> 44,469 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/5/5c/Downtown-Raleigh-from-Western-Boulevard-Overpass-20081012.jpeg" target="_hplink">here</a>.

  • San Jose, CA

    Metro area: San Jose-Sunnyvale-Santa Clara, CA<br> 44,189 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/9/9e/San_Jose_Basilica.jpg" target="_hplink">here</a>.

  • Rochester, NY

    44,066 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/e/e3/Colgate_8751.jpg" target="_hplink">here</a>.

  • Austin, TX

    Metro area: Austin-Round Rock-San Marcos, TX<br> 43,921 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/0/06/AustinSkylineLouNeffPoint-2010-03-29-b.JPG" target="_hplink">here</a>.

  • San Diego, CA

    Metro area: San Diego-Carlsbad-San Marcos, CA<br> 43,917 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/f/fa/San-diego-mission-chuch.JPG" target="_hplink">here</a>.

  • Riverside, CA

    Metro area: Riverside-San Bernardino-Ontario, CA<br> 42,293 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/1/18/Riverside_06Skyline.JPG" target="_hplink">here</a>.

  • Indianapolis, IN

    Metro area: Indianapolis-Carmel, IN<br> 42,213 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/1/18/Indiana_State_Capitol_Market_St.jpg" target="_hplink">here</a>.

  • Baltimore, MD

    Metro area: Baltimore-Towson, MD<br> 42,077 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/en/1/1f/E-mt.vernon.jpg" target="_hplink">here</a>.

  • Orlando, FL

    Metro area: Orlando-Kissimmee-Sanford, FL<br> 40,631 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/6/6b/Orlando_downtown_2011.jpg" target="_hplink">here</a>.

  • Virginia Beach, VA-NC

    Metro area: Virginia Beach-Norfolk-Newport News, VA-NC<br> 40,417 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/a/a9/Sunset-_Waves.JPG" target="_hplink">here</a>.

  • Miami, FL

    Metro area: Miami-Fort Lauderdale-Pompano Beach, FL<br> 38,058 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/a/a5/Mouth_of_Miami_River_20100211.jpg" target="_hplink">here</a>.

  • San Francisco, CA

    Metro area: San Francisco-Oakland-Fremont, CA<br> 37,796 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/d/da/SF_From_Marin_Highlands3.jpg" target="_hplink">here</a>.

  • Columbus, OH

    37,702 religious adherents per 100,000 persons. Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/d/db/ColumbusNightSkyline2.jpg" target="_hplink">here</a>.

  • Phoenix, AZ

    Metro area: Phoenix-Mesa-Glendale, AZ<br> 37,518 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/8/84/Phoenix_AZ_Downtown_from_airplane.jpg" target="_hplink">here</a>.

  • Denver, CO

    Metro area: Denver-Aurora-Broomfield, CO<br> 36,968 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/e/e9/DENCP.JPG" target="_hplink">here</a>.

  • Sacramento, CA

    Metro area: Sacramento-Arden-Arcade-Rosenville, CA<br> 36,512 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/7/7c/Sacramento_Skyline_%282%29.jpg" target="_hplink">here</a>.

  • Las Vegas, NV

    Metro area: Las Vegas-Paradise, NV<br> 35,761 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/7/7c/Sacramento_Skyline_%282%29.jpg" target="_hplink">here</a>.

  • Seattle, WA

    Metro area: Seattle-Tacoma-Bellevue, WA<br> 35,643 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/1/10/Seattle_Ferry.jpg" target="_hplink">here</a>.

  • Tampa, FL

    Metro area: Tampa-St. Petersburg-Clearwater, FL<br> 34,761 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/7/7b/Tampa_Florida_Lawyers.jpg" target="_hplink">here</a>.

  • Portland, OR-WA

    Metro area: Portland-Vancouver-Hillsboro, OR-WA<br> 31,591 religious adherents per 100,000 persons. <br> Credit: Wikimedia Commons. Original photo <a href="http://upload.wikimedia.org/wikipedia/commons/c/cc/TomMcCallWaterfrontPark.jpg" target="_hplink">here</a>.

Also on HuffPost: