Iowa’s unemployment rate dropped to 5.1 percent in April from 5.2 percent in March. The state’s jobless rate stood at 5.9 percent one year ago. The number of unemployed Iowans dropped to 85,200 in April from 86,800 in March, and from 98,500 one year ago. The total number of working Iowans increased to 1,578,200 in April from 1,575,700 in March. The current level is 12,100 higher than the April 2011 figure of 1,566,100. Job growth in April was heaviest in the goods-producing industries, primarily in construction and manufacturing. The private sector contributed 4,700 jobs, while government added 1,100, Iowa Workforce Development said in a news release. The national unemployment rate dropped to 8.1 percent last month.