Electoral system
Electoral rules place limits on suffrage and candidacy. Most countries's electorates are characterised by universal suffrage, but there are differences on the age at which people are allowed to vote, with the youngest being 16 and the oldest 21 (although voters must be 25 to vote in Senate elections in Italy). People may be disenfranchised for a range of reasons, such as being a serving prisoner, being declared bankrupt, having committed certain crimes or being a serving member of the armed forces. Similar limits are placed on candidacy (also known as passive suffrage), and in many cases the age limit for candidates is higher than the voting age. A total of 21 countries have compulsory voting, although in some there is an upper age limit on enforcement of the law. Many countries also have the none of the above option on their ballot papers.
Right of foreigners to vote
As voting is compulsory in Belgium, and all electors are automatically on the electoral rolls (extracted from a computerized National Register), foreign residents have to register voluntarily on the electoral roll, and only then are they subject to the obligation to vote. At the 2006 municipal elections, only 20.9% (110,973 out of 529,878) of the potential EU voters registered (17.6%, or 87,858 out of 498,315 at the 2000 municipal elections), and 15.7% (17,065 out of 108,607) of the potential non-EU voters.