 Meanwhile, all the states except Tasmania have electorates approximately within the same 10% tolerance, with most electorates holding 85,000 to 105,000 voters.Federal electorates have their boundaries redrawn or redistributed whenever a state or territory has its number of seats adjusted, if electorates are not generally matched by population size or if seven years have passed since the most recent redistribution.Voting is by the 'preferential system', also known as instant-runoff voting.