It is a party-list proportional representation, adopt a closed list system.
The nationwide proportional representation system was introduced for the first time in the 1963 election.
The system at that time was to allocate proportional representation seats according to the percentage of votes won by each party in the single-member constituency.
However, on 19 July 2001, the Constitutional Court ruled the system unconstitutional that it is against the principle of democracy to regard support for a candidate of single-member constituency as support for the party to which the candidate belongs.
In addition, half of seats of the proportional representation was allocated to the first party until the 1988 election, but it was abolished in 1990.