The Massachusetts Office of Labor and Workforce Development released new figures Thursday showing a drop in unemployment in April. The Bay State gained 2,500 jobs last month, dropping the unemployment rate to 6.3 percent, down from 6.5 percent in March. The professional, scientific and businesses services created the most jobs. Massachusetts also gained jobs in trade, transportation and utilities. According to the latest figures, the Bay State has added more than 31,000 jobs this year. The Connecticut unemployment rate remains static at 7.7 percent.