That analysis compared the number of people age 65 or older with the number of people under age 15.

An Old-Age Index greater than 100 means that there are more elderly people than minors. Specifically, the figure shows the number of elderly people in an area per every 100 young people.

The five municipalities on the island with the oldest population are in the west and include Hormigueros (with an index of 158), Mayaguez (137), Rincon (133), Lajas (129) and San German (127).

The five municipalities with the youngest population are Toa Alta (61), Peñuelas (66), Barranquitas (66), Morovis (67) and Santa Isabel (70).

The median age for the Puerto Rican population is 39, which is above the median age of 37 for the entire U.S. population, a situation that is in line with the phenomenon first observed in 2011 and which has remained the same since then.

In addition, about 26 municipalities have a average age of 40 or higher, proving the trend toward an aging population that is increasing due to the massive emigration of young people who are deciding to move to the U.S. mainland to find work and safety.

Young people with few job qualifications comprise the group that in recent years have been leaving the island most, according to an analysis published in April by the Federal Reserve Bank of New York.

According to the bank, the lack of jobs in Puerto Rico is the reason for the increase in emigration, a trend that has sharpened in recent years while the island’s economic crisis has worsened.

The analysis emphasizes that between 2001 and 2013 a third of those who emigrated to the United States were between 16 and 30 years of age, and this group is leaving the island at a much greater rate than any other grouping. Currently, a third of the people born in Puerto Rico live in the continental United States.

Emigration directly results in fewer taxpayers on the island just at a time when local authorities desperately need to find ways to increase tax revenues to balance the public accounts and pay for the growing medical expenses of an older population.