Out of the roughly 220 million Americans that have credit files maintained by the “Big Three” credit bureaus (Equifax, Experian, and TransUnion), about 1 out of 5 individuals have very poor credit, bad credit, or “deep subprime scores,” according to Experian.

Research from the credit bureau found that between the third quarter of 2006 and the second quarter of 2009, the number of people with really low credit scores rose more than 16% to 40 million.

The Number of Individuals with Bad Credit Is Rising

Meanwhile, the number of people with top-notch credit scores, so-called “superprime” consumers fell in 2009 primarily due to late payments from these once highly credit-worthy individuals.

One way that banks have responded to credit delinquencies – and other challenging business conditions – is by dramatically curtailing access to credit.

A September 2009 report from Experian found that in the prior 12 months, banks cut credit card lines by 17% to $3.1 trillion. And more cuts are expected.

Oppenheimer & Co. analyst Meredith Whitney has predicted that by the end of 2010, lenders will slash available credit to just $2.3 trillion – less than half of the $5 trillion that was available on credit cards in 2008.

Perhaps it is not surprising, then, that about 50 million adults in the U.S. have no credit files whatsoever – either because these individuals have never used traditional forms of credit, or because their credit files are “too thin” to generate a credit score.