2018 World Population Data Sheet With Focus on Changing Age Structures

PRB has produced its widely referenced World Population Data Sheet annually since 1962. This year’s edition provides the latest data on 26 key population, health, and environment indicators for the world, major regions, and more than 200 countries and territories.

Below are some highlights from PRB’s midcentury population projections in the 2018 World Population Data Sheet:

• The population of 26 countries, nearly all in Africa, will at least double. Niger in West Africa will see its population nearly triple.
• A total of 38 countries will have smaller populations in 2050 than in 2018. China will register the largest numerical population decrease―about 50 million―followed by Japan at 25 million and Russia at 9.4 million. Romania will see the largest percentage decline in population (23 percent).
• The population of the United States will reach 390 million, up from 328 million in 2018.
• China’s population will decrease by about 50 million from its current size to 1.34 billion. India will supplant China as the world’s most populous country with 1.68 billion people.
• Nigeria will become the third most populous country as its population rises to 411 million, up 109 percent from 2018. Nigeria is currently the seventh most populous country.

Changing Age Structures and Their Implications

The world population will also continue to age, with variations by country. By midcentury, projections indicate that 16 percent of the world population will be ages 65 and older, up from 9 percent now. The percentage of people in this age bracket in the world’s more-developed countries is projected to reach 27 percent, up from 18 percent now, while the percentage of adults ages 65 an older in less-developed countries is projected to double to 14 percent.

The 2018 Data Sheet’s special focus is on changing age structures around the world. Shifts in a country’s age structure over time can have important implications for a country’s economic and social trajectory, as well as its resource allocations and policy agendas. For example, many countries in the world are experiencing—and will continue to experience—steady increases in the number of older adults, both in absolute terms and as a percentage of the total population. This trend poses challenges for countries in balancing the pension, health, and other benefits that older adults typically receive with investments in the well-being of younger generations. In addition, some countries may choose to incentivize older adults to remain in the work force longer.

As part of the analyses for this Data Sheet, PRB demographers grouped countries into five age dependency categories to better illustrate their demographic challenges and opportunities. The categories were based on two factors: the child dependency ratio—the ratio of children (those under age 15) to the working-age population (ages 15 to 64); and the old-age dependency ratio—the ratio of older adults (ages 65 and older) to the working-age population.