There are 390 regular municipalities (gemeenten) and 3 public bodies (openbare lichamen), also referred to as special municipalities (bijzondere gemeenten), in the Netherlands. Municipalities are the second-level administrative division in the Netherlands and are subdivisions of their respective provinces. Their duties are delegated to them by the central government and they are ruled by a municipal council that is elected every four years. Municipal mergers have reduced the total number of municipalities by two-thirds since the first official boundaries were created in the mid 19th century. Municipalities themselves are informally subdivided into districts and neighbourhoods for administrative and statistical purposes.