preston council is elected in thirds, which means there is an all out election in one year followed by single-member elections in all three-member wards and selected two-member wards. all changes in percentage share of the vote are from the corresponding 2003 or 2004 elections in the respective wards. any "gain" or "loss" compares this year's elections with the 2002 "all out" vote because the councilors in this election are defending that year's result.