1. 1) Ministry of Internal Affairs and Communications, Statistics Bureau, “Estimate of the Population.”: 〈http://www.stat.go.jp/data/jinsui/index.htm〉, cited 6 June, 2011.
2. 2) Ministry of Health, Labour and Welfare, “Summary of Patient Survey.”: 〈http://www.mhlw.go.jp/toukei/list/10-20-2.html〉, cited 6 June, 2011.
3. 3) Ministry of Health, Labour and Welfare, “Survey of Medical Care Activities in Public Health Insurance.”: 〈http://www.mhlw.go.jp/toukei/saikin/hw/sinryo/tyosa08/2-4.html〉, cited 6 June, 2011.
4. 4) Ministry of Health, Labour and Welfare, Central Social Insurance Medical Council: 〈http://www.mhlw.go.jp/stf/shingi/2r985200000127vk-att/2r9852000001283s.pdf〉, cited 6 June, 2011.
5. 5) Yamane M., Inoue K., Endo H., Fujimoto Y., Amisaki Y., Shimao S., Morita T., Tabuchi H., Otsubo K., Med. Drug J., 34, 893-897 (1998).