American workers' productivity increased only slightly in the third quarter of 1990, rising at an annual rate of 0.2 percent, the government said.

The Labor Department's report also showed that the number of hours worked fell 0.2 percent in the July-September period, the first such decline in four years.Many analysts consider a decrease in hours worked a sign the nation's economic slowdown has been forcing businesses to make do with fewer employees.

The 0.2 percent third quarter increase in non-farm productivity - defined as output per hour of work - was under the 0.3 percent rise in the second quarter of 1990 but better than the 1.3 percent plunge in productivity during the first quarter of 1990.

The mediocre increases of the past two quarters and the big decline of the first three months of the year mean that productivity has fallen at an annual rate of 0.2 percent thus far in 1990.

Increased productivity, or getting each worker to produce more during each hour of work, is considered vital to boosting the nation's standard of living without inflation.

During all of 1989, productivity fell 0.7 percent.

Before the decline of 1989, productivity growth had averaged around 1.4 percent a year for the past several years, better than the 1.2 percent average of the 1970s, but far worse than the 3.3 percent annual gain posted in the two decades after World War II.