Unemployment rates declined across the country last month but many states still have daunting levels of joblessness to overcome. See the full interactive graphic. The unemployment rate dropped in 39 states last month and rose in three states and Washington, D.C., the Labor Department said Friday. The rate was flat in eight states. Nevada reported the highest unemployment rate, 12.5%, down 0.7 percentage point from a month earlier. The monthly change was the largest drop among all of the states. North Dakota had the lowest rate of joblessness last month, just 3.3%. Despite improvement in a most states, labor-market health varied widely in April. Midwestern states have experienced sharp declines in joblessness over the past 12 months after reporting double-digit unemployment in April 2010. Continue reading for an interactive map.