According to DISCUS (Distilled Spirits Council of the United States) a trade group, for the year ended December 2012, distilled spirit sales in California were the highest in the nation at 56,392,856 wine gallons. But since the US total is 494,726,495 wine gallons, it is a far cry from half. Otherwise Californians would be walking around totally blitzed all the time.
Next question, what’s a wine gallon? It’s a regular US gallon of 128 ounces. The term dates back to 1650 in England when a gallon measured 160 fluid ounces and we’ve no idea why DISCUS uses it.