Americans for Prosperity, a conservative outside group largely backed by the Koch brothers, spent $122 million in 2012, according to a new report from the Center for Public Integrity.

That sum is a huge jump from previous years for the organization, which aimed much of its money at attacking President Obama and his policies and targeting vulnerable Democrats.

Americans for Prosperity spent less than one fifth that sum in 2010, and just $7 million during the 2008 elections, before the Citizens United Supreme Court decision greatly deregulated campaign finance and allowed groups like this to focus part of their efforts on direct electioneering.

The group has kept up its heavy pace this year, with a number of ads attacking ObamaCare and targeting House and Senate Democrats facing tough reelection battles.