Although a standard definition is not available, the most common way to measure farm size is by the value of gross farm sales. USDA defines small farms as those having less than $50,000 in sales annually, representing 73% of the 2.1 million farms counted in 1992. It considers the remaining 27% of all farms (with sales of $50,000 or more) to be commercial farms. Although the 558,000 commercial farms counted in 1992 were a relatively small portion of all farms, they accounted for 88% of gross farm sales.