According to Wikipedia, NSA's share of Federal budget outlays was about 0.28% in 2013 (although there's a conceptual question whether you can just multiply your tax bill by 0.0028 to find out your contribution to NSA's budget, because Federal expenditures are also funded from sources other than personal income tax).

(Here I kind of wish we had a "facts we wouldn't know without Snowden" mock-HTML tag.)

All these comments about taxes are really making me regret creating that Irish shell corporation.

It's okay. Not every joke can be a winner.