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 Hong Kong
At the end of the 20th century, Hong Kong had one of the lowest birth rates in the world. However, the number of births doubled in the decade between 2001 and 2011, largely due to an increase in the number of children born in Hong Kong to women with residence in Mainland China. In 2001 there were 7,810 births to Mainland women (16%) out of a total of 48,219 births. This increased to 37,253 births to Mainland women (45%) out of a total of 82,095 births.