関連ワード:
why is there a low birth rate in japan why is there a declining birth rate in japan and south korea why is there a declining birth rate in japan why is there such a low birth rate in japan why is there a declining birth rate in countries like japan and south korea why is there a low fertility rate in japan why is japan's birth rate so low why is the birth rate declining in japan why is the birth rate falling in japan why does japan have a low birth rate
