WASHINGTON — Frugal shoppers cut back again in August, driving down sales at the nation’s retailers for the second month in a row, further proof the economy is losing traction. The Commerce Department reported Friday that retail sales dropped by 0.3 percent last month. Economists expected sales to rise by 0.3 percent. For the full story visit www.latimes.com/business/la-fi-econ13-2008sep13,0,301037.story