It'll take 300 years to wipe out child marriage at the current pace of progress

A 14-year-old schoolgirl in Bangladesh poses with friends and neighbors on her wedding day. A new UNESCO report looks at progress — and the lack thereof — in ending child marriage. (Sultan Mahmud Mukut/SOPA Images/LightRocket via Getty Images)

The world has made headway against the practice of child marriage, but progress has been frustratingly slow, according to a new report by UNICEF.

The percentage of women age 20-24 who were married in their childhood fell from 23% to 19% in the past decade. And yet, every year, 12 million girls across the world are married before the age of 18.