The little engine that could just ran out of steam -- after three months of gains, an index of small business indicators dropped in March.

The National Federation of Independent Business reports its Small Business Optimism Index fell 1.3 points to 89.5. That's below the index's average score of 90.7 since the recession ended in July 2009.

The index is based on a survey of 759 randomly selected NFIB members. Six of the index's 10 components declined in March, led by drops in expected sales and hiring plans.

"Virtually no owners think the current period is a good time to expand, because they simply don't know what the future holds," said NFIB Chief Economist Bill Dunkelberg. "So why invest?"

Overall, he added, "it appears that there will be little growth coming from the small business half of the economy; as the world economy slows, even big business may suffer."

Rep. Sam Graves, R-Mo., who chairs the House Small Business Committee, noted that the downturn in NFIB's index "mirrors other recent small business surveys and Friday's unemployment announcement."

"Small businesses are in a holding pattern amidst economic uncertainty and the burden of the health care law," Graves said.

"Many of the federal government policies being promoted by this administration are creating confusion rather than confidence," he said. "The recent decision to delay the Small Business Health Options Program is an example.”