MANILA, Philippines — The Philippines’ adult population is likely to be cut by 9 percent due to migration, according to a new Gallup poll, which also sees an exodus of young talents already at home.

Gallup released its potential net migration index (PNMI), which measures the total potential net change to the adult population by subtracting those who would like to move out of a country from those who would like to move into a country.

Results were based on telephone and face-to-face interviews with 453,122 adults — aged 15 and older — in 152 countries from 2015 to 2017.

The Philippines got a PNMI score of -9 percent, which indicates a net population loss, Gallup reported.

The poll also said 16 percent of the Philippines’ highly educated people will likely leave the country to work or live abroad. Educated residents are those who have completed four years of education beyond high school or have the equivalent of a bachelor's degree, Gallup explained.

Meanwhile, 13 percent of the Philippines' young population — aged 15 to 29 — wants to move out if everyone around the world could migrate where they wanted.

In Southeast Asia, only Singapore had positive scores in terms of attracting young and educated expats while Vietnam performed the worst in the region.

Overall, New Zealand got the highest PNMI score at 231 percent and would likely see an influx of young, talented migrants, Gallup said, while 70 percent of Sierra Leone’s total adult population wants to leave their home country if they had the opportunity — the worst in the survey.

“Gallup's Potential Net Migration Index does not predict migration patterns, but it provides useful information about the people these countries are attracting from around the world and the areas where leaders need to work to ensure they retain the talent already at home,” the report read in part.

The UN General Assembly last week formally ratified a deal that lays out 23 objectives to open up legal migration and discourage illegal border crossings.

A total of 152 countries, including the Philippines, voted in favor of the Global Compact for Safe, Orderly and Regular Migration. Twelve countries abstained while five nations voted against it — the United States, Hungary, the Czech Republic, Poland and Israel.

READ: UN General Assembly ratifies migrant pact | Philippines adopts UN Global Compact for Migration

“While critics of the agreement fear it would open the doors to unchecked mass migration, Gallup's latest Potential Net Migration Index actually shows that in most of the countries that are refusing to sign, more people want to leave them than come to them,” the pollster pointed out in its report.

“Hungary, for example, which became the second country after the U.S. to withdraw from the compact, could see its total adult population shrink by as much as 16 percent if everyone around the world moved where they wanted,” it added.