Hongsilp Sriket Dept. of Economics, Kasetsart Univ., 50 Ngam Wong Wan Rd., Chatuchak, Bangkok 10170, Thailand.   50 Ngam Wong Wan Rd., Chatuchak Bangkok, 10170 Thailand   fecohss@ku.ac.th             JEL Areas: O4 : Economic Growth and Aggregate Productivity: General D3 : Distribution: General