The latest sales numbers surrounding local food may prove the movement isn't a fad or simply a choice for the environmentally conscious. A new report from the U.S. Department of Agriculture's Economic Research Service (ERS) found that local foods netted American farmers $4.8 billion in 2008.

But the growth of farmers' markets or CSAs isn't the only factor at play: About 50 to 66 percent of all local food sales (called intermediated sales) come from grocery stores, restaurants and other retailers. Both direct-to-consumer and intermediated sales are captured together in this report for the first time. The ERS report did not designate between organic and conventional farms.

Although the $5 billion number sounds big, it represents just two percent of American agricultural sales, according to NPR, with sales of large commodities such as corn accounting for the rest. In comparison, local food revenue in 2008 was dominated by a large amount of vegetable, fruit and nut farms. These farms operate fewer acres, while generating higher gross sales per acre than field crops or livestock farms, according to the report.

Local food is commonly defined as food that's grown, distributed and sold within a radius of several hundred miles. But local doesn't necessarily mean small, says the USDA. Farmers captured in the report ranged from grossing $50,000 to more than $250,000 in sales. These local food farmers were also clustered in the Northeast and the West Coast regions and areas close to densely populated urban markets.