In the U.S as a whole, tax payers paid $4.7 trillion last year. Do you need me to explain why illegal immigrants contribution is miniscule by comparison?
As for the other numbers: You don't provide a source, and a quick google search shows no two estimates are alike. In other words, no-one knows how many illegal immigrants are employed, or in which fields. But who even cares? What's your point? Obviously having a large population of illegal immigrants in a country will mean they make up a percentage of certain sectors. Without them, the sectors shrink. So what? Then the sectors shrink, which is no problem for the country at large because, for one thing, the population at large also shrinks once you remove X million illegals.