If all the constituencies were the same size the main difficulty would be to establish whether the number of parties taking part was always the same. Since only so-called "useful" parties are considered this would be possible. Unfortunately, this is far from being the case. Only Iceland has 6 equal 9 seat constituencies while Irish constituencies are fairly uniform with 3, 4 or 5 seats. However constituencies in Belgium range from 24 to 4 seats, in Denmark from 16 to 2, in Finland from 33 to 6, in Luxembourg from 23 to 9 and so on.