Spiking gas prices helped drive retail sales in June up by a larger-than-forecast 0.6%. It was the largest jump since February and the second straight month of gains, which investors will likely seize as another sign of wider economic recovery. The Dow Jones Industrial Average was up 28 points at Tuesday's open (lifted also by higher commodities prices and strong quarterly results from Goldman Sachs). A jump in car sales after an historic industry slump also aided the month-to-month increase, which surpassed economists' expectations of a 0.4% gain. Petrol, however, was the prime mover, accounting for about half of June's increase. Overall, the most recent numbers, released by the Commerce Department Tuesday, were well below those registered in June 2008. This past month, U.S. consumers bought a total of $342 billion worth of goods at retail, down 9% from the year-ago level. Further, if you removed cars and the price-driven gasoline pump from the equation, things looked a little less rosy. Sales of general merchandise -- which includes department stores and other big chain retailers like Wal-Mart ( WMT) -- continued to decline, falling 0.4% from May, though that was a slower rate of contraction than the previous month's 1.7% drop.