Note: The 2017 National Population Projections were revised after their original release date March 13 to correct an error in the calculation of infant mortality rates. The files were removed from the website on August 1, 2018 and an erratum note was posted. The error erroneously caused an increase in the number of deaths projected in the total population. The revised calculation in the infant mortality rate results in a decrease in the number of deaths and a slight increase in the total projected population in the revised series. The error did not affect the other two components of population change used in the projections series (fertility and migration). Additionally, major demographic trends, such as an aging population and an increase in racial and ethnic diversity, remain unchanged.

The corrected data files are now available here. Six statements in the news release have been corrected. The first figure and one additional statement highlighted in red below were updated on Oct. 8, 2019. Please disregard any previous versions.

In less than two decades, the graying of America will be inescapable: Older adults are projected to outnumber kids for the first time in U.S. history.

Already, the middle-aged outnumber children, but the country will reach a new milestone in 2034 (previously 2035). That year, the U.S. Census Bureau projects [PDF] that older adults will edge out children in population size: People age 65 and over are expected to number 77.0 million (previously 78.0 million), while children under age 18 will number 76.5 million (previously 76.7 million).

This demographic transformation caused by a rapidly aging population is new for the United States but not for other countries. Japan has the world’s oldest population, where more than one in four people are at least 65 years old. Already, its population has started to decline and, by 2050, it is projected to shrink by 20 million people.

Europe is headed down the same demographic path. Some countries in Western Europe have populations that are older than the U.S., notably Germany, Italy, France and Spain. Countries in Eastern Europe are even further along and, within a few years, many of their populations are projected to begin shrinking.

America has been different, until now.

Higher fertility and more international migration have helped stave off an aging population and the country has remained younger as a result. But those trends are changing. Americans are having fewer children and the baby boom of the 1950s and 1960s has yet to be repeated. Fewer babies, coupled with longer life expectancy equals a country that ages faster.

Although declining fertility plays a role, the driving force behind America’s aging is the baby boomers. As one of the largest generations in the country, boomers leave a substantial imprint on the population. They swelled the ranks of the young when they were born and then the workforce as they entered adulthood.

Now, boomers will expand the number of older adults as they age. Starting in 2030, when all boomers will be older than 65, older Americans will make up 21 percent of the population, up from 15 percent today.

By 2060, nearly one in four Americans will be 65 years and older, the number of 85-plus will triple, and the country will add a half million centenarians.

With this swelling number of older adults, the country could see greater demands for healthcare, in-home caregiving and assisted living facilities. It could also affect Social Security. We project three-and-a-half working-age adults for every older person eligible for Social Security in 2020. By 2060, that number is expected to fall to two-and-a-half working-age adults for every older person.

If the trends continue, the U.S. is fast heading towards a demographic first. It will become grayer than ever before as older adults outnumber kids.

Jonathan Vespa is a demographer in the U.S Census Bureau's Population Division.