New figures from the Arizona Department of Revenue show monthly retail sales continue to increase but only in targeted economic sectors. The statistics show general merchandise sales, the largest category tracked by the state, down slightly from last year.

But, that was more than made up for by $660 million in car and truck sales, a 16 percent boost. Economist Elliot Pollack said it looks like people are picking and choosing how to spend money, especially if they have to take on debt.

“The interesting thing is that revolving credit is still declining,” Pollack said. “People are still paying off their credit cards, but they're willing to spend on autos.”

Pollack said that is because the average car is old, and a replacement is almost a must.

Economist Dennis Hoffman of Arizona State University agrees but thinks other factors, like low interest rates and better fuel efficiency, are also at work.

“What you've got going here is historically low automobile loan rates, interest rates, and an opportunity, then for people to buy new automobiles that are on the order of 10 to 15 miles per gallon more fuel efficient,” Hoffman said.

He said the combination of low interest rates and increased fuel efficiency is hard for people to resist, but he questioned how long the double-digit, year-over-year increases in sales can continue.