A sell-off in U.S. stocks sent the Dow Jones industrial average down more than 1,000 points today, erasing all the gains made so far this year.
The DJIA's fall was the biggest ever in terms of points, but on a percentage basis, it was only its 100th worst single day decline.
The DJIA's biggest percentage decline was on "Black Monday" on October 19, 1987, when it fell 22.6 percent.
