More high school students of minority backgrounds and from poor families are graduating, the U.S. Department of Education announced Monday. New data shows that not only does the high school graduation rate for the country as a whole continue to rise, but also that the increase was particularly pronounced among black, Hispanic and American Indian kids and for economically disadvantaged students.

Nationally, 81.4 percent of high school students graduated in the 2012-2013 school year, an increase from 80 percent the previous year. That figure included 86.6 percent of whites, 88.7 percent of Asians, 75.2 percent of Hispanics and 70.7 of blacks. Among low-income students, 73.3 percent graduated.

The department also published graduation data by state, showing variations in how well students of different groups do in high school. Blacks in Oregon, Nevada and Minnesota confronted long odds of graduating. The graduation rates for blacks in those states were 57 percent, 56.7 percent and 57.8 percent respectively, as shown in the map below.

The largest black-white gaps were in the Midwest. In Minnesota, although whites graduated at below the average rate for whites nationally, blacks did so poorly that there was a difference of 27.5 percentage points in the graduation rates.

In general, states with large gaps were those where blacks graduated at lower rates, as shown in the map below. Iowa was the exception, where blacks graduated at a rate close to the national average, but whites did exceptionally well. Iowa also boasted the highest graduation rate across all groups of any state (89.7 percent).

The smallest difference between blacks and whites was in Hawaii, where blacks did somewhat better than their peers elsewhere and whites somewhat worse.

In Texas, 84.1 percent of blacks graduated, the most in any state, and 85.2 percent of poor students graduated. They got their diplomas at an even higher rate in Kentucky -- 85.4 percent, well above the national average for high schools in general.

Another interesting set of comparisons is between the rates at which black students and economically disadvantaged students graduated. Overall, poor kids had a better chance of graduating than black kids, but in some states, economic class was more of a disadvantage than race. In Indiana, for example, poor kids of all races were nearly 9 percentage points more likely to graduate than the average black student, suggesting that black kids were doing badly for reasons besides the straightforward fact that many of them grew up in poverty.

In North Dakota, by contrast, black kids on the whole did 8 percentage points better than the low-income group. That figure implies not only that black students are doing well, but also that many of them are comparatively well-off, since their successes did not increase the average for the economically disadvantaged.

It's difficult to draw any firm conclusions from these maps, since so much inside and outside the classroom affects a child's chances of graduating from high school. A large gap between whites and blacks could reflect a public education system in which resources are directed toward schools with more white students, a discrepancy in incomes between members of each race or some combination of factors. A state with a high graduation rate for poor kids could be one where schools are especially good at overcoming the challenges of poverty, or it could be one where wealthier and poorer kids are more likely to live near each other. The concentration of poverty in urban ghettos puts poor kids in those neighborhoods at a double disadvantage.