A pair of studies from a leading credit reporting agency shows that credit card use continues to stabilize, especially in parts of the country hit hardest by the recession. Equifax's recent National Consumer Credit Trends Report measured increases in auto loans, student loans, and new credit cards. Meanwhile, a study of regional credit card debt shows that overall balances keep shrinking in cities where consumers bore the brunt of unemployment and declining home prices. For the first time since April 2010, the number of open American credit card accounts topped 300 million. While credit limits on those cards have risen above $1.87 trillion, consumers are only using about 22 percent of their available credit, Equifax researchers told reporters. Over $87 billion of that available credit originated this year, as banks grow more confident about their underwriting as consumers use credit cards more responsibly than in previous years. Researchers see evidence of the trend in Los Angeles, San Francisco, Detroit, Atlanta, Miami, and Phoenix. All six of those cities saw their residents' credit card debt drop by more than half a percentage point between August 2011 and August 2012. Even though Equifax research shows that overall credit card debt has leveled off across the United States, Equifax spokesman Trey Loughran told reporters that the figures in economically stressed cities reflected "the trend of the disciplined consumer." Loughran admitted that the statistics couldn't yet show a "long term change." Previous studies have shown mixed signals about whether American consumers have made only short term adjustments to economic pressure, or if this new attitude toward credit card debt reflects a new reality for lenders. Not every one of the 25 metropolitan areas in Equifax's study posted decreases in credit card debt, however. New York residents posted a gain of almost half a percentage point, bringing their collective balance above $49.6 billion. Houston residents contributed to the nation's sharpest rise in credit card debt. With nearly $11 billion in balances on Visa, MasterCard, American Express, and Discover-branded cards, they posted a 1.88 percent gain from the previous year.