Talk about taboo subjects: Most Americans would rather discuss their love lives with somebody they just met than how much they owe on their credit cards.

They would also rather talk about their salaries, mortgage or rent payments, health problems or religious or political views — anything, it seems, but credit-card debt, a recent poll shows.

''People who are faced with credit-card debt are unwilling to face their financial issues and therefore may be leaving them unresolved,'' said Ben Woolsey, director of marketing and consumer research for CreditCards.com. The online provider of credit-card information sponsored a survey of 1,000 Americans 18 and over that was conducted by GfK Roper Public Affairs and Media.

Thirty-five percent said they carry a balance on their cards, and 5 percent said they didn't know whether they do (I wonder, how can anybody not know?). But perhaps some people were not 'fessing up. Studies by the Federal Reserve and data released by credit-card issuers suggest the percentage of America households with card balances is at least in the mid-40s.

Maybe it is higher now, given the economic downturn. In a separate study commissioned by the Consumer Federation of America and Washington Mutual Bank (WaMu), nearly two-thirds of more than 1,000 people surveyed said they carry a revolving balance on at least one credit card.

In addition (here we go again), 8 percent said they did not know. And 15 percent said they have experienced at least ''some'' difficulty making the minimum payments.

This latest survey is the third conducted for the Consumer Federation and WaMu by Opinion Research Corp. (the others were in 2005 and 2007). These studies, focusing mostly on consumer understanding of credit scores, continue to show poor, although somewhat improving results.

For example, less than a third of Americans understand a credit score estimates the likelihood that a borrower will pay back a debt, including a credit-card balance.

Credit scores are based on, but are separate from, credit reports on our credit and loan application and payment history.

The three largest credit-reporting agencies are Equifax, Experian and TransUnion. The best known credit score is the ''FICO score'' named after the Fair Isaac Corp. that developed it (see Web site http://www.myfico.com).

The best way to improve one's credit score is by always paying bills on time. The higher the score — typical range is 300-850 — the better. Just 28 percent of Americans knew that a credit score of at least 700 is generally required to qualify for a low-rate mortgage (a 760 score might result in lower rates still).

More than a third did not know insurance companies often use credit scores to approve coverage and set rates. Less than three-fifths knew that regularly maxing out a credit card, even if paying bills on time, lowers credit scores.

In addition, 79 percent believed incorrectly that credit scores are available free once a year. That's true of credit reports only (see Web site http://www.annualcreditreport.com). Consumers generally have to pay for their scores, about $15 each.

''Consumer advocates fought very hard'' for free credit scores, said Stephen Brobeck, executive director of the Consumer Federation, but the law Congress passed in 2003 provided for free reports only.

Still, in addition to checking their reports once a year for accuracy, consumers are generally advised to check their scores perhaps every couple of years, or before they apply for a mortgage or other large line of credit. WaMu estimates consumers can reduce finance charges by $105 a year on average by raising their scores 30 points.