Sales at U.S. barbecue restaurants grew 7.2 percent to $2.9 billion in 2014, according to Chicago-based market research firm Technomic. The rate is nearly double the growth of the overall industry, where sales ticked up just 3.8 percent over the same period. The number of barbecue-focused restaurants jumped 8.1 percent to 1,942, with most of the growth coming from limited-service or fast-casual formats.