The Dow Jones industrial average closed more than 600 points lower Friday, only the ninth time in history that has happened.

The index posted a loss of nearly 666 points, its sixth-worst decline ever on a points basis.

The last time the index posted a drop of more than 600 points was June 24, 2016, the day after the Brexit vote.

The eight other times the Dow closed more than 600 points lower all took place in the last 18 years. Half occurred during the financial crisis in 2008.

The Dow closed more than 600 points lower Friday as Treasury yields rose, adding to worries about rates rising too quickly.

To be sure, as the Dow has soared over its nearly 122-year history, point drops increasingly represent a smaller percentage change. A roughly 666-point drop Friday was a decline of just 2.5 percent for the Dow. As recently as 2016, a fall of 600 points on the Dow marked a nearly 3.4 percent sell-off.

— With reporting by CNBC’s Robert Hum.