Because the myth was that the NSA was many times larger than the CIA. The reality is they pumped money into their Special Activities Division, which is a paramilitary division that gets involved in a lot of clandestine military actions. Usually they work side by side with DoD assets to accomplish military missions. This basically changes the notion that the CIA is simply a bunch of agents working out of embassies around the world to handle HUMINT assets that do the real spying. They still do that of course but they've become a much more hands on agency.

Half-jokingly, I will posit an alternative theory: The NSA is still the largest (has the most personnel), they just pay their people crap compared to CIA.

Because of Good Will Hunting: http://www.youtube.com/watch?v=UrOZllbNarw

"You guys handle 80 percent of the intelligence workload. You're seven times the size of the CIA."

Haha. Well, I wouldn't be all the surprised if the the NSA was bigger employee wise. But budget wise, no way.

Yeah if they are paying administrators 150k/year can you imagine how much a contractor for their SAD division makes? Probably a huge amount compared to the average modern mercenary.

NCS does not employ contractors for SOD (which I assume is what you meant by "mercenary", SAD includes non-tactical units too). Pay is relatively modest compared to other lines of work within the Agency.

Edit: I realized after I commented that I dropped alphabet soup all over the uninitiated. NCS is the National Clandestine Service, which is the division of the CIA responsible for covert operations. Most people assume the Special Activities Division (SAD) is only the Special Operations Group (SOG). There are no "mercenaries" within SOG, only Specialized Skills Officers, whom are recruited and transfered from other Special Forces branches.