The World Bank's data comes from the Gallup World Poll Survey, which found that
Being unbanked prevents the world's poor from saving for and investing in the future -- whether it be by paying for an education, buying a home, or starting a new business. The world's unbanked population is also at a disadvantage when it comes to borrowing.
There is a huge disparity between rich countries and the rest of the world when it comes to unbanked populations. Nine out of 10 adults in rich countries have a bank account, which is more than double the number of adults in developing countries with bank accounts, according to the World Bank. Just 18 percent of adults in the Middle East and North Africa and 24 percent of adults in sub-Saharan Africa have a bank account.
As a result, poor people are often forced to borrow money from informal lenders who generally charge high fees, according to the World Bank. Friends and family are the largest source of loans in all regions except for rich countries, where banks and credit unions are the most popular source of loans. About 40 percent of adults in sub-Saharan Africa have borrowed from friends or family in the past year, while about 5 percent of them have borrowed from an informal lender. An emergency or health care are the single largest reason why people in developing countries take out loans.
In the U.S., 7.7 percent of households are unbanked, according to the Federal Deposit Insurance Corporation.