The politicians who would be president have a lot to say about money, at least when they're soliciting it.

They and their sidekick superPACs have raised a combined total of around $1 billion, according to NPR calculations from data compiled by the nonpartisan Center for Responsive Politics.

But when it's time for a TV debate, the candidates aren't so eager to expound on their fundraising, the big donors they court for superPACs, or the legal rulings that give the wealthy more avenues for giving.

A new analysis by the liberal advocacy group Public Citizen finds that Bernie Sanders, Hillary Clinton and Donald Trump accounted for 92 percent of all commentary about political money and special interests in the 21 presidential primary debates through March 24.

The analysis, called The Elephant in the Room, also found that Sanders, Clinton and Trump were also the only candidates to talk about repairing a campaign finance system that has unexpectedly become a flashpoint for voter anger in this election cycle.

The full breakdown: Sanders, 53 mentions; Clinton 24; Trump 14; Ted Cruz 9; Carly Fiorina 3; once each by Jeb Bush, Ben Carson, Martin O'Malley, Mike Huckabee, Jim Webb and Lincoln Chafee. Five candidates — John Kasich, Marco Rubio, Chris Christie, Rand Paul and Scott Walker — never addressed campaign finance or special interests.

Public Citizen criticizes the debate questioners. In the 21 debates, they asked about political money in 15 of more than 1,000 questions. The analysis found no questions on candidates' views of the system or ways they would change it.

Lisa Gilbert, director of Public Citizen's Congress Watch, said she was surprised that the candidates and questioners made only 13 mentions of Citizens United, the 2010 Supreme Court ruling that has come to represent the surge in big-dollar politics.

Copyright 2016 NPR. To see more, visit