Data from the 2010 U.S. Census show that 14.5 percent of Puerto Ricans living on the island are 65 or older, revealing an aging society.

That proportion is double the 7 percent average for Latin America and the Caribbean, and is above the 13 percent figure for the United States as a whole.

Within the Caribbean, only Cuba, with 12.4 percent of its population over 65, has a profile similar to Puerto Rico's.

Demographer and University of Puerto Rico professor Jorge Duany told Efe on Friday that data from the 2010 Census reveal the island to be a society with signs of aging.

"Puerto Rico is in an advanced state of demographic transition," he said, noting that island's demographic profile increasingly resembles that of a developed nation.

Duany said that what is special about Puerto Rico is that the transition has occurred so quickly on the Caribbean island, while in other countries it typically takes much longer.

He recalled that in 1887, some 35 percent of the population was under 10, while those over 60 did not make up even 3 percent, a composition characteristic of a non-industrial society with high birth and mortality rates.

The birth rate in 1899 was very high - 40.5 births for every 1,000 residents, a figure that by 2009 had dropped to 12.9. Mortality had a similar evolution over the century, going from 25.3 deaths per 1,000 people in 1899 to 7.4 in 2009.

Duany said that the fundamental changes in Puerto Rican society occurred in the 1940s and '50s, when the transition to a society with a certain level of development took place.

That was possible, he said, thanks to the progress made in public health, an increased use of birth control and the emigration of millions of Puerto Ricans to the U.S. mainland.

The professor said that these changes have left Puerto Rico today as a society with a certain level of aging, which in turn means a series of challenges that will be hard to deal with.

"The phenomenon - of aging - has come about with such rapidity that no planning has been done," he said, and as an example mentioned the degree of medical attention needed by a society with such a large percentage of elderly people.