Elections have taken place, directly in every member state, every five years since 1979. there have been nine elections. When a nation joins mid-term, a by-election will be held to elect their representatives. This has happened six times, most recently when Croatia joined in 2013. Elections take place across four days according to local custom and, apart from having to be proportional, the electoral system is chosen by the member state. This includes allocation of sub-national constituencies; while most members have a national list, some, like the UK and Poland, divide their allocation between regions. Seats are allocated to member states according to their population, since 2014 with no state having more than 96, but no fewer than 6, to maintain proportionality.