As of 2015, which country has the highest population of people aged 100 years or older?

People who live to be 100 years of age or more are known as centenarians. There are more centenarians living today than ever before. The United Nations estimated there were 343,000 centenarians worldwide in 2012, a figure projected to grow to 3.2 million by 2050.

The United States has the most centenarians, with an estimated number of about 80,000, as of 2015. Japan follows, with an estimated 47,700.

Other countries with a relatively large number of centenarians include England and Wales, 12,320 in 2012 and Canada, 7,500 in 2011, the year of its latest census. Scientists agree longevity is a result of genetics, lifestyle, and environment.

In all countries, women centenarians outnumber their male counterparts. Most centenarians have been remarkably healthy over their life course, and experience relatively rapid terminal decline late in life such as demonstrating compression of mortality at the end of life.

Researchers on an Okinawa Centenarian Study, which has followed 8,000 Japanese American men in Hawaii, say many centenarians in their sample lived independently well into their 90s.

More than 90 percent of centenarians in their sample were still functioning independently at the average age of 93.

Some believe that gradual increases in living standards will result in similar patterns to those in Western Europe, where birth rates are declining rapidly. Others believe that the current world population is unsustainable.