How many illegals? Average number of illegals per employer. Calculate how many employers. From that you could figure how many investigators.
On that previously linked thread you said this to me:
"They have staticians, analysts, economists, etc. They have the Dept of Commerce, the Federal Reserve Bank, etc. This is their source of facts."
Well there you go, the government has at their disposal all those professional people and more so let them figure out how many investigators they need to get the job done. That's what we're paying them for.