The world's population will increase by 2.2 billion by 2050, and more than half of that growth will likely be in sub-Saharan Africa, according to a United Nations report released on Wednesday.

The report noted that the world's population reached 7.5 billion in 2017, and that the crude birth rate is 2.5, meaning that the average birth rate for women globally was two or three children last year. In sub-Saharan Africa, the birth rate was the highest, where women have four or more children. The report also revealed that the fertility rates are much lower in cities compared to rural areas in Africa.

If the prediction in the United Nations report is correct, African countries will make up 26 percent of the world population by 2050, up from 17 percent in 2017.

The report encourages countries across the globe to take measures to delay or prevent pregnancies based on women's choices.

"In developing countries, 671 million women have chosen to use modern contraception," said Monica Ferro, Director of the United Nations Population Fund in Geneva. "But at the same time, we know that 250 million in the developing world want to control their fertility, and lack access to modern contraceptive methods."

Ferro said that 300,000 women die during pregnancy or childbirth each year because they lack access to maternal health care, and that thousands of girls are forced into early marriage every day.