Washington: U.S. small business confidence in March fell slightly after rising for six straight months, a leading industry association said Tuesday.

The National Federation of Independent Business (NFIB) said its Small-Business Optimism Index decreased to 92.5 in March from a one-year high of 94.3 in February. Most notably, nine of 10 index components dropped last month.

The index gauging earning trends decreased four points to a net minus 23 percent, and the share of owners projecting higher sales, adjusted for inflation, dropped four points to a net 8 percent, Xinhua reported.

It also implied most of small business owners had no plan to create jobs and enhance inventory.

While still historically low, the latest increase is a sign that the recovery is likely to continue, noted the association, adding that gas prices spike would weigh heavy on small firms.

"The mood of owners is subdued, they just can't seem to shake off the uncertainties out there," said NFIB chief economist Bill Dunkelberg.

The March survey results ended what appeared to be steady, albeit slow, trend of improvement for the small-business sector of the economy, noted the association.

The small business industry, accounting for 99 percent of the overall companies, is the major drive of the U.S. economy and holds half of American labour force.