This doesn't sound like a huge difference. But when you're talking about millions of orders a day, it's significant. An annual study found the average drive-thru order takes 21 seconds longer now than it did last year.

From the moment you start your order to the moment you get your food, it takes an average of 4 minutes and 15 seconds. That's up from 3 minutes and 54 seconds last year.

Time of day makes a difference. The shortest wait is at breakfast, when the average order takes 3 minutes and 59 seconds. And the longest wait is in the late afternoon, when it's 4 minutes and 35 seconds.

Out of all the chains they looked at, Dunkin' Donuts had the shortest drive-thru times at 3 minutes and 37 seconds. And Chick-fil-A had the longest, 5 minutes and 23 seconds.

Wendy's was the second fastest at 3 minutes and 50 seconds. Then Burger King, 3 minutes and 55 seconds . . . Taco Bell, 4 minutes . . . KFC, 4 minutes and 4 seconds . . . and McDonald's was the second slowest at 4 minutes and 44 seconds.

Read more at QSR.