U.S. retail sales climbed 1.1 percent last month compared to August, the biggest monthly gain since February, the Commerce Department said Friday.

Spending on retail goods had risen by 0.3 percent in August and most analysts were forecasting an increase of approximately 0.8 percent in September.

Higher sales were reported in 10 of the 13 main retail categories last month, with car dealerships and clothing outlets leading the way.

Retail sales represent a substantial chunk of consumer spending, which in turn accounts for roughly 70 percent of U.S. economic activity.

The U.S. economy began growing again in July 2009 following the deepest and most prolonged recession in eight decades, but the rate of expansion has been very slow due to high unemployment, stagnation of real wages and consumer caution.

Auto sales rose 3.5 percent in September, the biggest monthly increase in a year and a half, with manufacturers selling almost 1 million units.

According to Autodata Corporation, which tracks auto sales, cars and light trucks sold at a seasonally adjusted annual rate of 13.1 million units in September.

That rate had climbed to as high as 13.2 million units in April before dropping due to a decline in the supply of cars and parts stemming from Japan's devastating March 11 earthquake and tsunami.

Excluding the auto sector, retail sales in September rose 0.6 percent, or two-tenths of a point above analysts' forecasts.