In 2004, Governor Howard Dean was the Dem's frontrunner. He led the pack by 15 points.

He dropped out a little more than a month later.

In 2008, Clinton had her first stint as frontrunner; she led by 19.2 points

Governor Rudy Giuliani topped the GOP on the first day of '08 by 3.5 points.

He quit 29 days later.

In 2012, former Speaker of the House Newt Gingrich was the frontrunner. He led by 2.2 points.

Gingrich left the race on May 2nd.

This video includes images from Getty Images.