A number of states allow voting in advance of election day. Early voting has a long tradition and is widely used, inter alia, in Iceland, Finland, Norway and Sweden where a substantial proportion of the ballots (around 19% in Iceland, 36% in Norway, 47% in Sweden and 51% in Finland) were advance votes in the last parliamentary elections of 2017, 2018 and 2019, respectively. Early voting usually takes place in designated advance polling stations, set up by municipalities (or foreign missions), but can also be conducted by mobile ballot boxes (see below). Whilst early voting enjoys a high level of public confidence and popularity in the abovementioned Northern European democracies, it should be noted that it requires a considerable administrative effort and is still not conducted in the same controlled environment as in polling stations on election day. Furthermore, in Norway, for instance, advance voters using voting locations outside their constituency are restricted in their election options because they cannot cast preferential votes for candidates, but only a party vote (by using a universal ballot or the available constituency ballot). In Iceland, blank ballots without any information on the election type or the candidate lists are used for early voting, and voting procedures differ considerably from voting on election day.