In the 12 months ended last October, quick-service doughnut restaurant customers indulged in 2.1 billion coffees, but only 805 million doughnuts.

Only 15 percent of quick-service doughnut restaurant purchases include both. Among those who visit these shops, 68 percent of the purchases include coffee. The coffee drinkers tend to buy specialty coffee drinks like lattes and frozen coffee. Specialty coffee orders at doughnut shops rose by 14 percent year over year for that 12-month period, while regular coffee servings declined by 4 percent.

Whether they went for the coffee or the doughnuts, though, consumers made 3.2 billion visits to quick-service doughnut outlets within those 12 months, up by 2 percent year over year. By comparison, traffic at all quick-service restaurants rose by just 1 percent. Visits to restaurants across the board remained static.

“We are a nation of coffee drinkers, and while we like our doughnuts, too, we tend to be fueled by coffee and drink more of it,” said David Portalatin, an NPD food industry adviser and the author of its Eating Patterns in America report. “The takeaway for doughnut shops: If you serve good-tasting coffee with your good-tasting doughnuts, consumers will visit.”