Relatively speaking, centenarians as a percentage of the overall population base are increasing. Naturally, estimates of the centenarian population can be hard to come by due to a variety of issues include verifying the ages reported, as centenarians might , a . However, available data suggest that the USA leads the world in terms of the sheer number of centenarians, followed by Japan, China, India, and Italy. According to estimates in 2015, the world was home to nearly half a million centenarians (people ages 100 and older). This was more than four times the estimated number in 1990. Projections suggest there will be 3.7 million centenarians across the globe by 2050.