1. 1) Ministry of Internal Affairs and Communications (2014) Vital Statistics.
2. 2) National Institute of Population and social Security Research (2012). Population and Projection for Japan: 2011 to 2060. http://www.ipss.go.jp/site-ad/index_english/esuikei/gh2401e.asp. Accessed April 21, 2016.
3. 3) The Ministry of International Affair and Communication (2015) Labour Force Survey.
4. 4) Japan Ministry of Health, Labour and Welfare (2016) Children and Childrearing.
5. 5) Gender Equality Cabinet Office, White paper (2013) "FY2003 Annual Report on the State of Formation of a Gender-Equal Society" and "Policies to be Implemented in FY2004 to Promote the Formation of a Gender-Equal Society".