WASHINGTON (AP) — American consumers' confidence has slipped after reaching an 18-year high last month.

The Conference Board said Tuesday its consumer confidence index fell to 127.7 in March. That was down from 130 in February, which was the highest level since November 2000.

Consumers were less optimistic in March as their assessment of business conditions declined, the Conference Board said. Their short-term expectations — including their outlook for the stock market — also declined, although overall expectations remain favorable. The percentage of survey respondents saying that business conditions are good increased from 36.5 percent to 37.9 percent, but those saying business conditions are bad also rose, from 11.3 percent to 13.4 percent.

The business research group's index measures consumers' assessment of current conditions and their outlook for the next six months.

"Despite the modest retreat in confidence, index levels remain historically high and suggest further strong growth in the months ahead," said Lynn Franco, the group's director of economic indicators.

Consumers were moderately less optimistic about the short-term outlook for business conditions in March. Their outlook for the job market also was less positive, despite the strong job market that has been boosting confidence in recent months. The unemployment rate has stayed at a 17-year low 4.1 percent; it's expected to keep falling to 3.8 percent at year's end.

Economists watch the Conference Board report closely because consumer spending accounts for about 70 percent of U.S. economic output.

The overall index hit bottom at 25.3 in February 2009 in the depths of the Great Recession before rebounding as the U.S. economy recovered.