How complete was the airwave pile-on against Newt Gingrich's surge in Iowa this month?

Half the ads in Iowa had a Gingrich focus. And the vast majority were negative, per a new analysis from the private Campaign Media Analysis Group (CMAG). It calculated that 45 percent of the political ads aired in Iowa were anti-Gingrich.

Only one in five negative ads was directed at Mitt Romney. One in 10 ads promoted Romney, according to Goldstein.

More from CMAG's Ken Goldstein:

We examined the tone and focus of advertising in Iowa since Dec. 1. The below breakdown shows how the focus of a majority of these ads has been on former Speaker of the House Newt Gingrich (51 percent). Unfortunately for him, most of the ads have been aired by his opponents - with fully 45 percent of all advertising in Iowa attacking Gingrich.

One in five ads hasttacked former Massachusetts Gov. Mitt Romney, with one in 10 ads promoting him. The difference between Romney's situation and Gingrich's is that many of the attacks on Romney were glancing blows delivered in ads that attacked multiple candidates. Ads attacking Gingrich tended to be solely and completely focused on him.

Anti-Gingrich: 45 percent

Pro-Gingrich: 6 percent

Anti-Perry: 8 percent

Pro-Perry: 8 percent

Anti-Romney: 20 percent

Pro-Romney: 10 percent

Pro-Paul: 3 percent