WASHINGTON — The number of workers who died on the job fell by 17 percent last year to the lowest level in nearly two decades, as workers logged fewer hours during the economic recession, the Labor Department said today.

The 4,340 workplace fatalities recorded in 2009 was the smallest total since the Bureau of Labor Statistics first began tracking the data in 1992. It's the second straight year that fatal work injuries have reached a historic low, following a 10 percent drop in 2008.

High unemployment and layoffs in more dangerous industries like construction played a major role in the decrease, the agency said. The construction unemployment rate is 17.3 percent, nearly double the overall jobless rate of 9.5 percent.

Workplace homicides declined 1 percent to 521 cases. That is nearly half the all-time high of 1,080 homicides recorded in 1994.