Good news, everyone: More than a billion human beings no longer suffer the miseries of “extreme poverty” — a level below sustenance for necessities such as food and shelter. “Poverty around the world is plummeting; half the world is now middle class; and illiteracy, disease and deadly violence are receding,” according to Wall Street Journal columnist Greg Ip.

Last year, more than half of the world’s 7.7 billion people reached a middle-class income or are even considered rich. Homi Kharas of the Brookings Institution and Kristofer Hamel of the World Data Lab crunched these numbers, calculating middle-class income as individual consumption between $11 and $110 a day in 2011 dollars.