The number of extremely poor people (defined as those earning less than $1 or $1.25 a day, depending on who’s counting) rose inexorably until the middle of the 20th century, then roughly stabilized for a few decades. Since the 1990s, the number of poor has plummeted.• In 1990, more than 12 million children died before the age of 5; this toll has since dropped by more than half.
• More kids than ever are becoming educated, especially girls. In the 1980s, only half of girls in developing countries completed elementary school; now, 80 percent do.