The TTU Economic Research Series comprises working papers and research briefs based on research from the Department of Economics and Finance, Tallinn University of Technology. Working papers are full-length papers issued to disseminate research results and to seek feedback. Research briefs are short papers in either English or Estonian (with an abstract in both languages) that make available early research findings, survey results or contributions on economic policy issues. For further information and for access to the TUT Economic Research Series, please visit www.tutecon.eu.