It would be interesting to see what at short term lowering of immigration would have on wage growth.
On the lowest rung of society, they're at least 50%. The higher you go the lower the percentage, and it drops off pretty fast.
I don't have exact figures so I'm using 50% like "about half". I suspect though that it's only about half because some of them managed to legalize themselves, and in reality in these very bad jobs there's actually even more than that.