it is very difficult to determine this. Companies that do h1Bs are all multinational, so they can locate dev offshore and just say they did it internally. There's also the reality that even if you go out and try to evaluate the revenue that comes from IT, you basically can't get clean attribution even if you want to. many H1Bs are not working on customer facing product, but internal projects and that makes treating things like application maintenance or service desk pretty difficult to calculate for ultimate revenue outcome.