International Institute for Democracy and Electoral Assistance: Pintor and Gratschew, ed.'s "Voter Turnout since 1945: A Global Report"
Read pages 13-19 and 75-88. Compare and contrast the turnout rates for different countries and consider the variables (social, economic, and political) which contribute to a country's propensity for its citizens to exercise (or not exercise) their right to vote.
Click Full-Text-English-Voter-Turnout-Since-1945-A-Global-Report.pdf link to view the file.