By Ruth Mantell
WASHINGTON (MarketWatch) -- Sales at U.S. retailers were unchanged in July, the weakest result in six months, as sales fell at auto dealers, but rose at gas stations and food and beverage stores, according to government data released Wednesday. Excluding autos, retail sales rose a seasonally adjusted 0.1% last month, the U.S. Commerce Department reported. July's results missed expectations among economists polled by MarketWatch, who had forecast overall retail-sales growth of 0.2% in July, matching June's result. Excluding autos, economists had expected July retail-sales growth of 0.4%, also matching June's result. Retail sales are a major chunk of consumer spending, which is the backbone of the U.S. economy. Data details show that auto sales fell 0.2% in July. Meanwhile, sales rose 0.3% at food and beverage stores and 0.1% at gas stations.