How could you possibly know that 100% of them are "natural born citizens?" All of them where born in P.R., and to "citizen" parents?
Puerto Rico was ceded to the USA after the Spanish American as spoils of War. They were given full American citizenship many decades ago. There are more Puerto Ricans living in the USA than in the islands. My neighbor across the street is a dual service 38 year veteran E-9, and even fought in Grenada and Panama.
If you are born on US soil, you are a US citizen regardless of your parents’ nationality.
Regions with significant Puerto Rican populationsPuerto Rico (2013) 3,466,804
United States (2016) 5,450,472
Puerto Ricans became citizens of the United States as a result of the passage of the Jones-Shafroth Act of 1917. Since this law was the result of Congressional legislation, and not the result of an amendment to the United States Constitution, the current U.S. citizenship of Puerto Ricans can be revoked by Congress,[69] as they are statutory citizens, not 14th Amendment citizens.[70] The Jones Act established that Puerto Ricans born prior to 1899 were considered naturalized citizens of Puerto Rico, and anyone born after 1898 were U.S. citizens, unless the Puerto Rican expressed his/her intentions to remain a Spanish subject. Since 1948, it was decided by Congress that all Puerto Ricans, whether born within the United States or in Puerto Rico, were naturally born United States citizens.
Anybody born in PR is a US citizen. Regardless of parents.
Puerto Ricans are automatically U.S. citizens. If they're not Puerto Ricans, they're not automatically U.S. citizens.
Was that hard?