Massachusetts’ unemployment rate remains at its highest level in two years, while the number of jobless workers has grown to 250,000. According to the state Executive Office of Labor and Workforce Development, in August there were 250,000 unemployed workers in Massachusetts and the unemployment rate remained at 7.2 percent, its highest level in nearly two years. Nationally, the unemployment rate has been decreasing; at 7.3 percent, it is still slightly higher than Massachusetts’ unemployment rate.