Massachusetts four-year high school graduation rates climbed for the ninth year in a row in 2015 with some of the largest gains recorded by some minority groups and students from low-income families. The second-largest school district in the state, Springfield, boasted the best improvement of any urban district in the state.

Across the state, 87.3 percent of students who entered high school in 2011 graduated four years later, a 1.2 percent increase from last year’s rate, according to data released by the Massachusetts Department of Elementary and Secondary Education. The state’s drop-out rate declined to 1.9 percent, the lowest in 30 years.