(AP) — Statistics show a big jump in the number of vineyards in Iowa, though the industry remains small compared with states such as California.In 2000, Iowa had only five vineyards that covered about 15 acres. Iowa State University Extension viticulture specialist Mike White said that's now grown to 310 vineyards that stretch out over 1,200 acres. Iowa's roughly 100 wineries place the state in the top 20 nationally for the number of wineries. White said Iowa winemakers in 2012 sold a total of about 300,000 gallons of wine, making up more than 5 percent of the wine sold in the state.John Burns, the owner and winemaker of Barrel Head Winery just outside Dubuque, said his customers are especially interested in area wines. Burns noted that he produces wine from the grapes he grows on his land, unlike some other Iowa wineries that use grapes grown elsewhere.