The regions were created on 1 January 2007 to replace the 16 former counties. At the same time, smaller municipalities were merged into larger units, reducing the number from 270. Most municipalities have a population of at least 20,000 to give them financial and professional sustainability, although a few exceptions were made to this rule. The administrative divisions are led by directly elected councils, elected proportionally every four years; the most recent Danish local elections were held on 21 November 2017. Other regional structures use the municipal boundaries as a layout, including the police districts, the court districts and the electoral wards.