And this, from the archives: publicintegrity.org/federal-politi…
Per @OpenSecretsDC (it's been a while since I totaled this up myself), the group spent $15.8 million to influence elections in 2012 and $9.5 million in 2010.
This list gives us some donors, but we still don't know where the money that came from, say, the Wellspring Committee originated.