Akihiro Otsuka Socio-Economic Research Center, Central Research Institute of Electric Power Industry   1-6-1 Otemachi, Chiyoda-ku Tokyo, 100-8126 Japan   akihiro@criepi.denken.or.jp   http://criepi.denken.or.jp/en/           JEL Areas: R : Urban, Rural, and Regional Economics R1 : General Regional Economics (includes Regional Data)