Americans continue to rely on credit and debit cards as primary means of paying for goods at point-of-sale (POS) terminals, according to a new report from First Data Corporation.

In May, overall card spending at retail locations was up 7 percent year-over-year, which is a higher growth rate than the previous month (5.7 percent). Consumers spent at healthy rates during the beginning of the month (which is when Mother's Day occurred), but spending continued to be strong throughout the course of the month. The number of overall transactions held steady at 5.9 percent.

"Overall May card spending growth was healthy, but there is reason for caution. During the month we saw consumers reducing the growth of their discretionary spending at retail merchants and increasingly resorting to credit for necessities," said Silvio Tavares, senior vice president and division manager of First Data Global Information and Analytics Solutions.

Father's Day falls on June 17 this year, and early reports from the National Retail Federation expect the holiday to cause another boost in spending. Although Americans don't typically spend as much on dad as they do on mom, the NRF study suggests the gap is slowly closing – good news for retailers.