I’d say estimates in TX are 50-60% of construction workers are undocumented.
Personally, based on what I’ve seen, I think the number in CA is FAR higher than 20-23%. My office about 15 years ago was adjacent to a huge condominium construction site and it looked like 100% of the workforce was minority, mostly Mexican (but probably other Central American workers, too). How many are illegals? Half?