I'm betting that 18% includes people forced onto contracts because many companies no longer hire full time employees or require "contract" work before making a full time offer.
It includes people who are tired of obtaining a "permanent" position only to have the entire department liquidated 2-3 years later. Repeatedly. As a contractor, I can have multiple clients, which makes it less likely for them to all "fire" me at the same time.
That's fine, I'm not talking about people in your situation. Personally I'd probably do the same if I didn't need a consistent stream of income and health insurance to support my family. But there are a large number of IT workers out there that are on "contract", but are treated as an employee. This is basically labor fraud, and it should be stopped.