Have you made up your mind about how you will vote in the forthcoming referendum?
As a matter of interest these are by no means the only voting systems used around the world, though some kind of proportional systmes do seem to be in the majority.
First Past The Post (FPTP) 51 countries
Block Vote (BV) 15 countries
Party Block Vote (PBV) 4 countries
Alternative Vote (AV) 3 countries
Two-Round System (TRS) 21 countries
List Proportional Representation (List PR) 71 countries
Single Transferable Vote (STV) 2 countries
Mixed Member Proportional System (MMP) 8 countries
Parallel Systems 20 countries
Single Non-Transferable Vote (SNTV) 2 countries
Limited Vote (LV) 1 country
Borda Count (BC) 1 country
No direct elections (N) 15 countries (including China)
for an explanation of each see: http://www.idea.int/esd/glossary.cfm#N