We’ve been credit carding it up (yep, it’s a verb) lately and as a result, Americans have collected more credit card debt than we had a year ago during the same time period, according to new figures from a credit reporting agency. But while we’re spending more, we’re not being so good at actually paying off that debt — which makes for a particularly unwinning economic combination.

TransUnion says credit card debt in the U.S. between July and September grew 4.9% over last year’s figure, to about $4,996, according to the Associated Press.

Meanwhile, we’re also slacking off and paying off our credit card payments late by a rate of 0.75%, a 0.04% uptick from 2011. That’s not totally awful because we were at very low levels of overdue payments. So even though it’s rising a bit, the trend of paying off debt that we all caught on to during the recession is still a relatively popular one.

“We definitely see consumers being more conservative in their spending and making every effort to pay down the balances and maintain the health of those card relationships,” said the vice president of TransUnion’s financial services business unit.

We could also be carrying higher balances on our cards because of seasonal factors — tis the time to buy stuff and then pay it off later in the spring. Or we’re just so darn confident in the economy with the recent hiring improvements, we’re not as hesitant to splash out with our credit cards.

There is a big potential downside to this rise in card balances, however. It could be partly due to banks handing out more credit cards to people, even if they don’t have great credit. That practice could come back to haunt consumers who get in over their heads with how much they’ve spent.

“Lenders are absolutely issuing more credit in the nonprime space,” said the TransUnion VP. “The size of the pie is bigger and nonprime consumers are getting a larger share of that pie.”

Even in the midst of the holiday buying blitz, now is a good time to tell yourself again that you will end up having to pay for that giant TV — with interest. Making payments on time is a key factor to having good credit, as missing even one payment could jack your interest rate up into the sky-high range.

Average US credit card debt per borrower up in 3Q [Associated Press]

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