What does 'registered' mean in this sense. In the UK we can join a political party if we wish, even then we are not obliged to vote for that party, or even to vote at all. Our biggest problem is voter apathy, so few people bother to vote. This can cause an area with 60000 people on the electoral register to return a candidate who gets 20% of the vote, in which maybe only 35% of the electorate voted. This means that 4200 people decide the representation of 60000, it's all wrong.
Giok