U.S. retail sales, a key barometer of the country’s economic health, increased in July by the most in four months.

The government’s Commerce Department said Friday that consumers spent more on autos, furniture and gasoline last month, helping push retail sales up by one-half of one percent, following a slightly smaller increase in June.

Consumer spending accounts for 70 percent of the U.S. economy, so consumer spending trends are watched closely. The July spending increase was the country’s biggest since an advance of eight-tenths of a percent in March.

High unemployment and rising gasoline prices slowed the U.S. economic recovery earlier in the year. Gas prices have moderated lately, leaving a bit more cash in consumers’ pockets.

However, many stock investors have worried this week as the country’s stock markets have whipsawed wildly between losses and gains after Standard & Poor’s downgraded the country’s credit rating a week ago.

Back-to-school sales promotions helped boost some consumer spending last month, as did increased new car sales. Nine of the 13 categories measured by the government showed increased sales.