WASHINGTON, Oct 15 - U.S. shoppers took a pause from their breakneck shopping pace in September, as retail sales fell for the first time since April, the Commerce Department said on Wednesday. Commerce said retail sales fell a larger-than-expected 0.2 percent overall to a $320.58 billion in September. Excluding the slumping auto sector, however, sales actually rose a modest 0.3 percent. While the numbers came in slightly below Wall Street analysts' forecasts, gains in previous months were revised upward, which may prod economists to raise their forecasts of third-quarter economic growth. August sales were revised to a 1.2 percent increase from a previously reported 0.6 percent gain, while July sales were revised up to a 1.4 percent advance from a 1.3 percent gain. In September, auto sales slid 1.6 percent, their biggest drop since February. But other sectors, including building materials and clothing, took up the slack, posting strong gains. Economists watch retail sales closely to track trends in overall consumer spending, which makes up about two-thirds of U.S. economic activity. Wall Street economists surveyed by had expected a smaller 0.1 percent decline in September sales and a 0.4 percent gain in sales excluding autos.//