Small business owners grew slightly more optimistic about their economic outlook in September even as more firms planned to cut staff than hire new workers, a survey showed on Tuesday.

The National Federation of Independent Business (NFIB) said its optimism index edged up 0.2 points to 89.0 in September — the latest sign of sluggishness in the U.S. economic recovery.

Boosting the index, the number of firms reporting increases in capital outlays in the last six months rose to 45 percent, up 1 percentage point from a month earlier but still near a 35-year low, the NFIB said.

"The downturn may be officially over, but small business owners have for the most part seen no evidence of it," said William Dunkelberg, the group's chief economist.

The U.S. recession ended in June 2009 but the recovery slowed dramatically in the second quarter.

Investors bet the Federal Reserve will pump billions of new dollars into the economy soon to spur growth.

The NFIB poll showed 16 percent of small businesses plan to cut jobs over the next three months, up from 13 percent in an August survey.

Only 8 percent expected to hire workers.

The country shed jobs for a fourth straight month in September, hit by government layoffs and slower private hiring.