The world population will reach 9.8 billion in 2050, up 31 percent from an estimated 7.5 billion now.

The world youth population (ages 15 to 24) is projected to rise to 1.4 billion in 2050 from 1.2 billion now but the youth share of the world popup will fall to 14 percent from 16 percent.

These are according to projections included in the 2017 World Population Data Sheet from the Population Reference Bureau (PRB), available to the Ghana News Agency.

This edition of the annual Data Sheet, also shows a worldwide total fertility rate (TFR, or average lifetime births per woman) of 2.5.

The three countries with the highest TFRs are Niger (7.3), Chad (6.4), and Somalia (6.4), while there is a five-way tie for the lowest TFR (1.2) among Bosnia-Herzegovina, Romania, Singapore, South Korea, and Taiwan.

PRB’s widely referenced Data Sheet has been produced annually since 1962.

This year’s edition provides the latest data on 17 key population, health, and environment indicators for the world, major regions, and more than 200 countries.

Special Focus on the youth

This year’s Data Sheet also includes nine special indicators and six analytical graphics assessing whether youth (generally defined as people ages 15 to 24) are well-positioned to develop into productive adults, based on health, education, and other factors.

The Data Sheet includes indicators for secondary and tertiary school enrollment, adolescent fertility rates, rates of HIV/AIDS among youth, youth population figures for 2017, and youth population projections for 2050.

The Data Sheet's mid century population projections indicate that India will become the world's most populous country with 1.7 billion people, with China in second place at 1.3 billion.

Again, it said India will register the largest numerical increase in population of any country, adding 323 million people by 2050.

Nigeria, however, will post the second largest rise at 220 million, followed by Democratic Republic of Congo at 134 million.

It said 39 countries will have smaller populations in 2050 than in 2017. China will register the largest numerical population decrease of 44 million, followed by Japan at 25 million and Ukraine at 9 million.

It said the population of 30 countries, nearly all in Africa will at double by 2050.

The population of the U.S. will be 387 million, up from 325 million today. A few key figures of the youth

Africa’s youth population will rise to 35 percent of the world youth total in 2050, from 20 percent today.

Ethiopia currently has the highest share of youth population at 21.8 percent while Bulgaria has the lowest share at 9.1 percent.

The global adolescent fertility rate (ages 15 to 19) is 50 births per 1,000 women, compared to only 16 per 1,000 in more-developed countries and 54 per 1,000 in less-developed countries.

The analytical features focusing on youth explore the extent to which youth are engaged in productive activities (such as education, employment, or training) in the United States and globally, the prevalence of modern family planning use among young married women, HIV/AIDS rates among African youth, the prevalence of behaviors among youth that can lead to noncommunicable diseases, and in the digital edition, level of access by youth to information and communication technologies.