List of electoral systems by country

This is a list of electoral systems used to elect national legislatures and heads of state, organised by country in alphabetical order.
References.
Much of the data on Bulgaria from Central electoral committee - "Methods for determining the number of mandates in constituencies and the results of the vote" (in Bulgarian); A mathematical analysis of the system
Much of the data regarding which voting system is used is drawn from this 2002 report from the International Institute for Democracy and Electoral Assistance (IDEA).
Much of the data regarding the size of the parliaments comes from this 1997 report from the same Institute.
Some of the data has been updated since then.