More than one quarter of all U.S. households are “unbanked” or “underbanked”, according to a study by the Federal Deposit Insurance Corp. (FDIC) released Wednesday. (See the study)

The study, The FDIC National Survey of Unbanked and Underbanked Households, classified respondents as unbanked if they didn’t have a savings or checking account, and classified them as underbanked if they had a checking or savings account but relied on nonbank money orders, nonbank check-cashing services or payday loans.

The survey found that 7.7 percent of U.S. households (9 million) are unbanked and 17.9 percent (21 million) are underbanked, for a total of 25.6 percent. Iowa fared better than the national average. Only 4.7 percent of Iowa households are unbanked and 16.8 percent are underbanked, for a total of 21.4 percent. (see a full breakdown of Iowa results)

The study found that a large proportion of the unbanked Americans are minorities. Only 3.3 percent of white households are unbanked, compared with 21.7 percent of black households, 19.3 percent of Hispanic households and 15.6 percent of American Indian/Alaskan households. Among Asian-American households, 3.5 percent are unbanked.

The survey also found that households with incomes under $30,000 account for at least 71 percent of unbanked households. Nearly 20 percent of low-income households earning less than $30,000 per year do not have a bank account. Only 4.2 percent of households with an annual income between $30,000 and $50,000 and fewer than 1 percent of households with an annual income of $75,000 or higher are unbanked.