In America, what you earn depends largely on your success in school. Unfortunately, your success in school depends largely on what your parents earn. It's an intergenerational Catch 22 that's at the heart of modern poverty.

Keep that in mind while looking at the monstrously depressing map up above, which comes courtesy of a new report by the Southern Education Foundation. In 2011, there were 17 states where at least half of all public school students came from low-income families, up from just four in 2000. Across the whole country, 48 percent of kids qualified as low income, up from 38 percent a decade earlier.

To be crystal clear, the researchers were not analyzing poverty rates per se. Rather, they tracked at the percentage of children in each state who received free or reduced school lunches, which are only available to students whose families earn below 185 percent of the poverty line. For a family of four, that amounted to about $41,000 in 2011—a figure that might feel dire in New York City, but less so in New Mexico. In the end, we are talking about families poor enough to get some amount of federal food help.

More troubling than the strict number of low-income students, however, was the long-term trend. As I noted up above, the number of states handing out cheap and free meals to more than half their students quadrupled in ten years, a point that this Washington Post illustration hammers home vividly. American public school students are becoming poorer.