Four North Coast breweries rank among the 50 largest craft brewers in the United States, according to a list published Thursday by an industry trade group.

Lagunitas Brewing Co., the fast-growing Petaluma company, became the sixth-largest craft brewer in the nation last year, the Brewers Association reported Thursday. It was the ninth-largest craft brewer in the U.S. in 2011.

Eleven of the 50 breweries are located in California. Bear Republic Brewing Co. in Healdsburg moved up one spot to 34th place; Lost Coast Brewery in Eureka dropped two spots to 38; and North Coast Brewing Co. in Fort Bragg dropped four spots to 42.

Anderson Valley Brewing Co. in Boonville, which was tied for 50th place in 2011, dropped off the list last year.

The rankings were based on overall beer production, but the Brewers Association did not release the figures used to calculate the list.

The largest craft brewer nationally remained Boston Beer Co., brewer of the Sam Adams line. Second place remained Sierra Nevada Brewing Co., based in Chico.

The association defines craft breweries as those that are independently owned and produce less than 6 million barrels per year, or 186 million gallons, though very few come anywhere close to that figure.

Although the industry has grown substantially in recent years, craft brewers still accounted for only about 6.5 percent of the beer sold in the U.S. last year. Even Boston Beer Co. was dwarfed by the major market brewers, placing fifth nationally behind Anheuser-Busch, MillerCoors, Pabst Brewing Co., and D.G. Yuengling and Son Inc., according to the Boulder, Colo., trade group.