In 2012, 3.55 million workers in the U.S. worked for $7.25 an hour or less, according to a recent Pew Research report that analyzed U.S. Bureau of Labor Statistics data. This number includes workers who are exempt from the minimum wage law, such as tipped employees, full-time students and certain groups of disabled workers, but does not include salaried employees.

Minimum-wage hourly workers were disproportionately young, white, female, more likely to live in the South and employed only part-time, according to the study, and 44 percent of them work in restaurant, food-preparation and related occupations.

Here’s a closer look at the occupations that employ the highest numbers of minimum-wage employees: