An increasing number of Americans are ditching $10 sandwiches and $12 salads in favor of food from home, according to new data from the research firm NPD Group. Lunch traffic is slowing at restaurants around the country, with weekday lunch visits down 7 percent compared to a year ago, the steepest decline since the beginning of the recession, data show.

The reason? Nearly 40 percent of Americans now work from home (at least on some days), according to Gallup, and lunch out is becoming too expensive for many to justify.

“The price-value relationship at lunch has gotten out of whack,” said Bonnie Riggs, a restaurant industry analyst for NPD Group. “Part of it has to do with sticker shock. When you’re paying $12 for a sandwich and drink every day, well, who can afford that?”