5% of American households have no bank account at all - either because fees are too high or because they have cashed bad checks or failed to pay bank fees in the past and are now refused an account.

Another 25% had their bank balance go below zero in the past year. And that number is worse than it sounds, because it doesn't include people who have selected to have transactions fail instead of put their balance below zero. https://www.consumerfinance.gov/data-research/research-repor...