The two megabrewers each lost 3% of their market share apiece last year as craft, regional and imported beers all gained ground. Craft beer grabbed 5.7% of all beer production last year and 9.1% of all revenue, according to the Brewers Association industry group. Imported beer sales also jumped 1% last year after a 5% leap in 2010. That combined growth means a lot more Corona ( STZ ), Yuengling and Samuel Adams in local coolers, but it also means a whole lot of growth for beer styles and brewing and delivery methods once considered marginal among U.S. brewers. Samuel Adams maker Boston Beer ( SAM ), for example, recently put some of its increased revenue into expanding its barrel rooms and small-batch brewing facilities in Boston.