The organisation of local government in England is complex, with the distribution of functions varying according to local arrangements. The upper-tier subdivisions of England are the nine regions, now used primarily for statistical purposes. One region, Greater London, has had a directly elected assembly and mayor since 2000 following popular support for the proposal in a referendum. It was intended that other regions would also be given their own elected regional assemblies, but a proposed assembly in the North East region was rejected by a referendum in 2004. Since 2011, ten combined authorities have been established in England. Eight of these have elected mayors, the first elections for which took place on 4 May 2017. Below the regional tier, some parts of England have county councils and district councils and others have unitary authorities, while London consists of 32 London boroughs and the City of London. Councillors are elected by the first-past-the-post system in single-member wards or by the multi-member plurality system in multi-member wards.