The research was led by Estelle Sommeiller, a socio-economist at the Institut de Recherches Economiques et Sociales in France, and Mark Price, a labor economist at the Keystone Research Center in Harrisburg, Penn. Price told NPR that since 1979, "in almost every state, there's been more growth in income for the top one percent, than for the bottom 99 percent [of Americans]."
And while the last few years have seen the U.S. recovering from the worst financial crisis since the Great Depression, economist Justin Wolfers writes in The New York Times that, setting aside capital gains "which are largely enjoyed by the rich, it remains the case that nearly all the fruits of that recovery have gone to the rich."
There are some exceptions. In West Virginia, incomes of the top one percent actually fell, while the rest of the population's grew. Incomes rose both for the top one percent and for the rest of the population in Indiana, Mississippi, Montana, North Dakota, Vermont, New Mexico, Kentucky, Alaska and Hawaii.
North Dakota 99 percent's income lags amid energy boom
Mark Price highlighted North Dakota as an extreme example. The income of the bottom 99 percent has grown by 21 percent since 2000. That's because they've been riding an energy boom which has created millionaires. "At the same time," Price said, "the top one percent in North Dakota's income grew by 103 percent. You still see the national pattern, which is that most of the growth is going to that tiny fraction of folks."
Not all states have benefited in the same way from the energy boom. Pennsylvania has also been exploring its energy resources, but its unemployment has been in line with the national average.
"The numbers here are much worse," said Price. "The bottom 99 percent have actually lost ground, and the top one percent have seen growth of about 28 percent." That, Price explained, is in part because the oil and gas industry doesn't typically employ as many people as, say, the health industry. But it's also because Pennsylvania has over 17 times the population of North Dakota, and a far more diverse economy, so it's harder to make a dent in a recession.
A Morgan Stanley poll of over 300 millionaires found that most of them list the "increasing income gap between poor and wealthy Americans" as a top concern.
And while 2015 is expected to bring more growth in income for all sectors, Price said his concern is that the results are going to continue looking a lot like North Dakota: most of the gains will go to people at the top.