Using government debt data and census data, IndexCreditCards.com has determined that the average American adult is carrying $4,150 in revolving debt (mainly credit card debt) and the average American household is carrying $7,980 in such debt.

Data released earlier this month from the Federal Reserve Board estimates that revolving consumer debt in the United States totals over $955 billion. Using census data from 2006 to the present, IndexCreditCards.com estimates the adult (18 and over) population of the U.S. at 230,265,970 and the total number of households at 119,756,270. Dividing the total revolving debt by the population/household figures gives the resulting debt averages.

(Federal Reserve surveys suggest that about 75% of households have at least one credit card, and 25% have none. If we count only those households that report actually having one or more credit cards, the average household credit card debt would be $10,640.)

While still quite high, these numbers are actually down from the averages we reported back in October of 2008, when the average debt per adult was $4,150 and the average per household was $8,188. While the bleak economy might suggest that credit usage would increase, the economy has also caused many lenders to pull back on credit offers. In addition, many consumers have severely cut back on spending as their earning outlooks have become more cloudy.

Revolving debt is mainly debt from credit cards, although related revolving consumer debt such as home equity lines of credit are included as well. A caveat: Not all revolving debt is long-term debt accruing interest — some of this debt is paid off each month. (Although pinpointing how much debt gets paid off every month is difficult, various surveys have reported that 40% to 55% of card holders say they pay off their full balances every month.)

Weekly Averages:

• Average consumer credit card rate, overall market: 14.17%
• Average credit card rate, non-reward consumer cards: 12.80%
• Average reward credit card rate: 14.76%
• Average student credit card rate: 14.15%
• Average business credit card rate (non-reward): 11.77%
• Average business reward credit card rate: 12.84%

Interest rates on consumer credit cards jumped significantly this week, with Bank of America raising rates on some of its main offers, as well as a few hikes by other issuers. The average rate for credit cards across all consumer sectors jumped to 14.17%, the highest rate thus far in 2009, and up from 13.89% three weeks ago.

(In pinpointing a single “average” rate, IndexCreditCards attempts to include all of the various rate tiers that card issuers offer based on an applicant’s credit history, as well as the different rates associated with non-reward versus reward cards. Consumers with better credit histories can often find offers well beneath this average, while those with bad credit histories will likely be offered rates higher than the average.)

The average credit card rate for non-reward consumer credit cards increased to 12.80%, up from 12.47% previously, while the average rate on credit cards with rewards jumped to 14.76%, up from 14.50%.

While the averages listed above attempt to take into account the multiple tiers that many credit card issuers offer, IndexCreditCards.com also tracks the very lowest listed rates, those reserved for customers with the very best credit. This week those averages were also up, to 11.21% for the market as a whole (previously 10.84%), with a 9.77% average for non-reward cards (previously 9.29%) and a 11.83% average for consumer cards with rewards (previously 11.50%).

Bucking the trend, curiously enough, were student credit cards, whose average rate fell to 14.15% from the previous average of 14.26%. Are students really getting these lower rates, or are card companies using them as teasers before offering higher rate cards? It’s hard to say, but published offers do suggest that student rates have become virtually equal to those of the consumer market in general. If this is indeed true, it would be unprecedented, as student rates are generally much higher than those offered to older adult consumers.

Business credit card rates, which have been on the rise recently, have stalled, with no changes since last month. The average rate for non-reward business credit cards remain at 11.77%, while the average rate for business credit cards with rewards remains at 12.84%.

Financial institutions represented in the survey include Advanta, American Express, Bank of America, Capital One, Chase / Washington Mutual, Citi, Discover, PNC/National City, Pulaski Bank, U.S. Bank, Wells Fargo, and more.