Ranked from biggest tool to outside interests to smallest, based on percentage of PAC money to the total raised through February 2016, reported here:
Rick Perry: 91%
Jeb Bush: 78%
George Pataki: 71%
Chris Christie: 69%
Scott Walker: 61%
Carly Fiorina: 54%
Mike Huckabee: 53%
Marco Rubio: 50%
*Ted Cruz: 46%
Lindsey Graham: 44%
Rand Paul: 42%
Bobby Jindal: 41%
*John Kasich: 30.2%
Rick Santorum: 30%
*Hillary Clinton: 28%
Martin O'Malley: 15%
Ben Carson: 14%
Jim Webb: 13%
*Donald Trump: 5%
*Bernie Sanders: 0.1%
*still in the race
(watch the gif here)