An index meant to gauge the future strength of the U.S. economy fell slightly in April, marking its first decline in more than a year, a private industry group said on Thursday.

The Conference Board said its index of U.S. leading economic indicators slipped 0.1 percent last month, surprising analysts who had been looking for a 0.2 percent gain.

It was the first drop since March 2009.

The index, which aims to forecast growth six to nine months out, had risen to record highs in recent months.

These latest results suggest a recovery that will continue through the summer, although it could lose a little steam, said Ken Goldstein, economist at the Conference Board.

The report's findings are consistent with the consensus forecasts of market economists, who see growth tapering off modestly in the second half of 2010 after a robust start to the year.

U.S. gross domestic product rose an annualized 3.2 percent in the first quarter, according to government data. That was a third quarter of growth following the longest recession in more than 70 years.

(Reporting by Pedro Nicolaci da Costa; Editing by Andrea Ricci)