Iowa’s seasonally adjusted unemployment rate dropped to 4 percent in March from 4.1 percent in February, Iowa Workforce Development reported. That’s the lowest rate since May 2008. The state’s jobless rate was 4.4 percent a year ago. The U.S. unemployment rate remained at 5.5 percent in March. “Nonfarm employment increased for the sixth-consecutive month in March, adding 3,300 jobs,” said Iowa Workforce Development Director Beth Townsend. The number of unemployed Iowans decreased to 67,800 in March from 70,300 in February. The current estimate is 6,200 lower than the year-ago level of 74,000. The total number of working Iowans increased to 1,647,100 in March. This figure is 600 higher than February and 25,500 higher than last March.