The older age profile in the United States population has significantly grown from what it was 16 years ago, according to estimates by the U.S. Census Bureau population.

The median average age has grown from 35.3 years old on April 1, 2000 to 37.9 years old on July 1, 2016.

Population for residents 65 years old or older grew 14.2 million in a 16-year span, from 2000 (35 million) to 2016 (49.2 million). This now accounts for 15.2 of the population, which is nearly a three percent uptick.

According to the data, two-thirds (66.7 percent) of the nation’s counties in 2016 had an increase in median age. Two counties in particular had median ages over 60 years old; Sumter, Florida (67.1) and Catron, New Mexico (60.5).

Also, during the 16-year span, 95.2 percent of all counties experienced an increase in their median age.

California did not make the top five, but these states led with the highest median ages in 2016 - Maine (44.6), New Hampshire (43), Vermont (42.7), West Virginia (42.2 ) and Florida (42.1).

“The baby-boom generation is largely responsible for this trend,” said Peter Borsella, a demographer in the Population Division for the census bureau. “Baby boomers began turning 65 in 2011 and will continue to do so for many years to come.”

Whatever factors have contributed to this increase must continue because it's leading to more longevity.