U.S. retail sales rose for a second consecutive month in August, helped by higher gasoline and automobile prices, the government said in a report Friday that pointed to modest economic growth in the third quarter. The Commerce Department said retail sales increased 0.9 percent last month, the biggest gain since February. Retail sales rose a downwardly-revised 0.6 percent in July. The rise in August retail sales was led by gasoline stations, reflecting a sharp increase in gasoline prices. Gasoline sales soared 5.5 percent, the biggest increase since November 2009, after rising 0.4 percent in July. Auto sales increased 1.3 percent, the most since February, after gaining 0.1 percent the previous month. Excluding gasoline and autos, retail sales rose only 0.1 percent last month after increasing 0.8 percent in July. "Core" retail sales, which exclude gasoline, autos, and building materials, fell 0.1 percent in August after increasing 0.8 percent the previous month. Such sales correspond most closely with the consumer spending component of the government's gross domestic product (GDP).