A lot of it. I teach illegals ESL. I have several couples who left their children in Nicaragua and came here to work. One woman and her husband were here for 4 years and just got their son up here. I can guarantee you that they work to get money back to their families. They live in large groups in trailers to save money. I like these people a lot and admire them. But I don't see how they are helping the economy as much as this article says.
FINANCING THE MEXICAN INVASION
http://www.freerepublic.com/focus/f-news/1750489/posts
What's even worse is the fact that the program will be subsidized by taxpayer dollars.
I believe the problem is more a failure to assimilate than a failure to make money.
This is exactly how they are helping the US economy. We spend 11,000 a year to educate a kid in the US public school system and probably another 11k per kid that the parents kick in. If you dump the kids off in Nicaragua, you can spend probably one tenth that much.