US announces $450M to increase access to rooftop solar power in Puerto Rico
energy.gov
energy.gov
https://www.irs.gov/taxtopics/tc901
"If you're a bona fide resident of Puerto Rico during the entire tax year, you generally aren't required to file a U.S. federal income tax return..."
I'm having a hard time finding hard data, but the last number I could find, from 2010, showed the island paying $20 million total in individual federal income taxes, on a population of 3.7 million.
And the exemption is if you are getting money from anywhere stateside. US government obviously qualifies, but so do a lot of other cases.