The following chart lists the different voting systems used by the world's 33 major, well-established democracies -- meaning countries with high human rights ratings and at least two million inhabitants. Proportional representation (PR) systems are by far the most common.
Of the six nations that don't use PR to elect representatives in their most powerful national legislative body, only three countries (the United States, Ghana, and Canada) don't use it for at least one of their national elections: PR is used to elect the upper house in Australia and members of the European Parliament in France and the United Kingdom (although it would appear that no future European Parliament elections will be held in the United Kingdom following the pending British exit from the EU).
*Countries with a population of at least 2 million with a 2017 Freedom House Average Freedom Score less than 2.Summary of Totals:
- Proportional Representation (20)
- Plurality (4)
- Parallel (4)
- Mixed-Member Proportional Representation (2)
- Instant Runoff Voting (1)
- Single-Transferable Vote (1)
- Runoff (1)
Source: Mark P. Jones, the Joseph D. Jamail Chair in Latin American Studies and the James A. Baker III Institute for Public Policy’s Political Science Fellow at Rice University.