Enkhmaa Battogtvor Graduate School of International Social Sciences, Yokohama National University   Minami ward, Ooka 2-31-2 Ooka International Residence 201 Yokohama, Kanagawa 232-0061 Japan   battogtvor-enkhmaa-wg@ynu.jp             JEL Areas: F4 : Macroeconomic Aspects of International Trade and Finance: General Q3 : Nonrenewable Resources and Conservation: General