영어 해석좀 도와주세요;;

Singapore's recent history of immigration goes a long way toward explaining its rich cultural diversity. For many years, the government of Singapore had liberal immigration policies. The country needed foreign workers partly due to its low birthrate : there are only. 78 birth per woman, which is below the replacement rate of 2.1. By 2005,, 40 percent of the population was made up of residents from other parts of Asia, North America, and Europe.

 

여기서 저 밑줄쳐진 부분이 도저히 이해가 안되네요..

 

78 birth per woman 이면 여성 한명당 78명을 낳는다고 해석되는데 무슨 동물도 아니고 말이되나요? ;;

 

영어 잘하시는분들 도와주세요 !!