Unemployment rates fell throughout the Washington region in April as employers strained to fill their needs for technology workers and other employees, District and federal labor department reports showed yesterday.</br></br>The low jobless rates demonstrated a widespread demand for workers. Regionwide, only 3.3 percent of adults seeking work were unemployed in April, down from 3.4 percent in March and 3.6 percent in April a year ago. The unemployment rate in the suburbs dropped from 3 percent in March to 2.9 percent in April, according to D.C. Department of Employment Services data that are not adjusted for seasonal work patterns.</br></br>The District's jobless rate sank to 7.2 percent in April from 7.8 percent the month before, including seasonal adjustments.</br></br>But employment in the region grew by only 1.8 percent over the 12 months ending in April, a clear measure of the difficulty employers are having finding workers, economists said.</br></br>By far, the strongest job growth over the year was in high-tech categories, prompting some analysts to wonder how long technology companies can continue to lead the economy ahead.