“People have been feeling optimistic and, when they do, it is tempting to use credit cards,” said Kimberly Palmer, a NerdWallet card analyst.

Many US consumers have not resisted temptation. Debt levels have been rising for years. US households now owe $13.15 trillion in total debt, about $931 billion of it card debt, according to NerdWallet’s 2017 American Household Credit Card Debt Study along with its newly issued quarterly figures.

The average household card debt is close to $16,000. That comes with hefty interest bills.