Carson City saw a 3.6 percent increase in taxable sales in December, reporting a total of $72.6 million in sales.The biggest driver in that increase was the 21.4 percent jump in auto sales, which came in just over $18 million. The only other major category in the capital to see a solid increase was food services and drinking places — up 4.2 percent to $7.4 million.The other major category, General Merchandise Stores, increased just 0.4 percent to $16.89 million. Wholesalers of both durable and nondurable goods were down.Statewide, merchants sold $4.3 billion in goods in December, on which the state collected $336.5 million in gross sales-and-use taxes. The revenue collection is up 3.6 percent for the month and 5.6 percent for the fiscal year that began July 1.Construction categories were up nearly 25 percent for the month and accommodations up 38 percent. Food services and drinking places reported a 5.4 percent increase — a major contributor to the overall 6 percent increase in Clark County.For the month, the portion of taxes that feed the state general fund totaled $84.2 million, representing a 2.1 percent increase over December 2011. But for the fiscal year, those collections are $9.3 million below the forecast made Nov. 30 by the Economic Forum, an independent panel of business experts that projects how much money the state will have to spend in the next two years.The forum’s projections are used to build the state budget, and the governor and lawmakers are barred by law from exceeding forum predictions when setting spending unless a new revenue source is specified.Sales-and-use taxes account for about 30 percent of general fund revenues.Douglas County reported an 8.1 percent increase for the month, with $62.7 million in sales. Food services and drinking places, Douglas’ largest tax generator, was up 7.5 percent to just over $12 million. The surprise, however, was the jump in the miscellaneous manufacturing category, which went from $125,530 to more than $4.8 million in December. Details of what happened there were unavailable.Lyon County’s sales decreased 4.7 percent to $41 million.• The Associated Press contributed to this report.CountyTaxable SalesChange from 12/11Statewide$4.34 billion3%Carson City$72.65 million3.6%Churchill$28.53 million -34.6%Douglas$62.7 million8.1%Lyon$41 million -4.7%Storey$7.8 million28.4%Washoe$552.16 million -4.7%Clark County $3.17 billion6%