(NBBJ) - The total economic impact of Napa County’s grape and wine business last year was $13.3 billion inside the county line, $25.9 billion in California and more than $50 billion in the U.S., according to a study released today by a local trade group. These estimated effects on the local, state and national economies resulted not only from production of wine from the county’s 789 wineries to domestic and foreign markets but also sales of grapes from the county’s 43,500 acres of vines, distribution and retail markups on that wine, sales of suppliers to the industry, tourist spending but also wages at these various businesses, according to the 19-page study by Napa-based Stonebridge Research for Napa Valley Vintners.