According to the Regionalverband Ruhr (RVR, Ruhr Regional Association), 37.6% of the region's area is built up. A total of 40.7% of the region's land remains in agricultural use. Forests account for 17.6%, and bodies of water and other types of land use occupy the rest. The inclusion of four mainly rural districts in the otherwise mainly industrial Ruhr helps to explain the large proportion of agricultural and forested land. In addition, the city boroughs of the Ruhr region have outlying districts with a rural character.