Food stamps turns 50 this year. Since the program was written in to law, it’s become one of those government programs that gets a lot of attention from politicians on both the left and the right — especially recently. 

The program has been growing furiously in the past 15 years. In fact, one in seven Americans is on food stamps today. That’s more than twice what the rate was in 2000. Some of that can be explained by changing eligibility requirements and job-losses during the recession. But the fastest growing group of food stamp participants in the last few decades are people who have jobs and work full year-round.

In our series on The Secret Life of a Food Stamp, Marketplace Wealth & Poverty Desk reporter Krissy Clark reports on how big retail chains that employ these workers also themselves take in tens of billions of dollars in food stamps.

In this video, produced by our series partner Slate, we estimate how much more Wal-Mart might have to charge for some products, if it raised wages high enough that a typical worker earned too much to qualify for food stamps.

Note: Eligibility for food stamps varies according to income, number of dependents and other factors. This estimate of Walmart’s potential cost from raising wages is based on wages for a Walmart employee with one dependent working 30 hours a week, a typical retail worker based on federal data.