Liquor privatization in Washington was voter approved and took effect in June.
The average price of a liter of booze, including taxes, rose 11.6 percent to $24.09 in September from $21.58 at state liquor stores a year ago, the data show.
Liquor sales by volume, meanwhile, rose 2.9 percent from June through September, compared to the same period last year. Consumers purchased 7.9 percent more spirits during the period, while bars and restaurants bought 12.6 percent less.
Bars and restaurants may have purchased less because they stocked up on booze before privatization took effect. Higher prices, weaker demand and supply issues also may have been a factor, according to the state Department of Revenue.