PR-STV provides proportionality by transferring votes to minimise waste of votes, and therefore also minimises the number of unrepresented voters. In this way PR-STV provides "Droop proportionality" - an example STV election using the Droop quota method for 9 seats and with no exhausted preferences would guarantee representation to every distinct group of 10% of the voters, with at most just under 10% of the vote being wasted as unneeded excess. Unlike other proportional representation methods employing party lists, voters in STV do not explicitly state their preferred political party (with the exception where above-the-line voting systems are in place); this in turn can create some difficulty when attempting to analyse how an STV election's results compare with the nationwide partisan makeup. One common method of estimating the party identification of voters is to assume their top-preference on their ballot represents a candidate from their preferred party, however this method of estimation is made more complicated by the possibility of independent candidates and of cross-party voting. However valid comparisons have and can still be made if sufficient data and information are available. In Victoria, Australia, it is possible to make a direct comparison between the Australian Senate election and the Victorian Upper House elections although individual circumstance will always exist. Voting patterns have shown that most voters stay with their chosen party within a limited percentage range based on local issues and circumstances. The main advantage in Victoria's case is that both systems are similar in design with one being a subset of the other. Victoria held its first multi-member proportional representation election in November 2006 for the Legislative Council