The world is aging so fast that most countries are not prepared to support their swelling numbers of elderly people, according to a global study being released Tuesday by the United Nations and an elder rights group.

The report ranks the social and economic well-being of elders in 91 countries, with Sweden coming out on top and Afghanistan at the bottom. It reflects what advocates for the old have been warning, with increasing urgency, for years: Nations are simply not working quickly enough to cope with a population graying faster than ever before. By the year 2050, for the first time in history, seniors over the age of 60 will outnumber children under age 15.

Truong Tien Thao, who runs a small tea shop on the sidewalk near his home in Hanoi, Vietnam, is 65 and acutely aware that he, like millions of others, is plunging into old age without a safety net. He wishes he could retire, but he and his 61-year-old wife depend on the $50 a month they earn from the tea shop.

"People at my age should have a rest, but I still have to work to make our ends meet," he says, while waiting for customers at the shop. "My wife and I have no pension, no health insurance. I'm scared of thinking of being sick — I don't know how I can pay for the medical care."

Thao's story reflects a key point in the report, which was released early to the Associated Press: Aging is an issue across the world. Perhaps surprisingly, the report shows that the fastest aging countries are developing ones, such as ­Jordan, Laos, Mongolia, ­Nicaragua and Vietnam, where the number of older people will more than triple by 2050. All ranked in the bottom half of the index.

The Global AgeWatch Index (www.globalagewatch.org) was created by elder advocacy group HelpAge International and the U.N. Population Fund, in part to address a lack of international data on the extent and impact of global aging. The index, released on the U.N.'s International Day of Older Persons, compiles data from the U.N., World Health Organization, World Bank and other global agencies, and analyzes income, health, education, employment and age-friendly environment in each country.

Much of the world is not prepared to support the ballooning population of elderly people. This man is Filipino.

The index was welcomed by elder rights advocates, who have long complained that a lack of data has thwarted their attempts to raise the issue on government agendas.