of Basque nationalist parties Union, Progress and Democracy (, UPyD) Commitment Coalition (), a coalition of Valencian parties, now in a coalition with Más País. Citizen's Forum, Democracy and Freedom (Democràcia i Llibertat or DiL) Yes to the Future (). In addition, the Aragonese Party, United Extremadura, and the Union of Navarrese People participated in the 2011 elections forming regional coalitions with the People's Party. Electoral process Suffrage is free and secret to all Spanish citizens of age 18 and older to all elections, and to residents who are citizens of all European Union countries only in local municipal elections and elections to the European Parliament. Congress of Deputies Elections to the Cortes Generales are held every four years or before if the prime minister calls for an early election. Members of the Congress of Deputies are elected through proportional representation with closed party lists where provinces serve as electoral districts; that is, a list of deputies is selected from a province-wide list. Under the current system, sparsely populated provinces are overrepresented because more seats of representatives are allocated to the sparsely populated provinces than they would have if number of seats are allocated strictly according to the population proportion. Not only provinces with small population are over-represented in Spain's election system, the system also tends to favors major political parties. Despite the use of proportional representation voting system, which in general encourages the development of a larger number of small political parties rather than a few larger ones, Spain has effectively a two-party system in which smaller and regional parties tend to be underrepresented. This is owing to various reasons: Due to the great disparity in population among provinces, even though smaller provinces are overrepresented, the total number of deputies assigned to them is still small and tends to go to one or two major parties, even if other smaller parties managed to obtain more than 3% of the votes – the minimum threshold for representation in the Congress. The average district magnitude (the average number of seats per constituency) is one of the lowest in Europe, owing to the large number of constituencies. The low district magnitude tends to increase the number of wasted votes (the votes that could not affect the election results because they have been cast for the small parties which could not pass the effective threshold), and in turn increase the disproportionality (so the