From Wiki: Currently, the United States Census Bureau estimates that the population of Puerto Rico was 3,667,084 on July 1, 2012, a -1.6% decrease since the 2010 United States Census. From 2000 to 2010, the population decreased, the first such decrease in census history for Puerto Rico. It went from the 3,808,610 residents registered in the 2000 Census to 3,725,789 in the 2010 Census.
A declining and aging population presents additional problems for the society. The Census Bureau has noted that “76,218 people residing in the U.S. last year lived in Puerto Rico one year earlier.”
10 year drop from 2000 to 2010 was 2.2%. In just two years another 1.6% of the population has left PR, averaged over ten years that would be roughly a 8% drop in population. That is significant.
I would suspect they are coming to the mainland looking for opportunity as they can get welfare by staying in PR. There would be no point in moving for that. I would also think those coming to the states are more upwardly mobile (which presents yet other challenges for the remaining pop.)
For those complaining that PRs moving to the states can vote in presidential elections it goes both ways. If you move to PR you cannot vote in presidential elections. (Unless you ilegally maintain a US address for voting purposes).
Go to any welfare office in Orange or Osceola counties, and you will see that the vast majority of Hispanics are from PR. Bennies in FL are much more generous than in PR, and the cost of living is lower as well.