What percentage of full-time, white-collar workers pack lunch?

My husband is a white collar worker and he brings his lunch almost every day of the week. My husband takes his lunch to save money. Also, he does not have time every day to go out to lunch. It helps him that I make home cooked meals and make sure there are enough leftovers for him to take to work every day. He tells me that there are a lot of people that do pack their lunch every day.