Birth rate
As of 2017, Niger has the highest birth rate in the world with 49.443 per thousand people. 
Japan has one of the lowest birth rates in the world with 8 per thousand people.
While in Japan there are 126 million people and in Niger 21 million, both countries had around 1 million babies born in 2016.
Demographics of Niger
Niger's high infant mortality rate is comparable to levels recorded in neighboring countries. However, the child mortality rate (deaths among children between the ages of 1 and 4) is exceptionally high (274 per 1,000) due to generally poor health conditions and inadequate nutrition for most of the country's children. Niger's very high total fertility rate (6.89 children born per woman, which is the highest in the world), nonetheless, means that nearly half (49%) of the Nigerien population is under age 15. School attendance is low (34%), including 38% of males and 27% of females. Additional education occurs through Koranic schools.