According to Radio Netherlands, prostitution is concentrated in and around the big cities and in the border towns in the regions of Limburg, Groningen, Twente, West Brabant and Zeeland. Prostitution occurs in various forms: window and street prostitution, clubs, escort agencies, and home-based prostitution. Window prostitution occurs in 12 cities in the Netherlands. It is estimated that on average some 2,000 prostitutes are engaged daily in this form of prostitution. Street prostitution exists in 10 Dutch cities and involves on average some 320 prostitutes daily. Between 3,500 and 4,000 prostitutes are employed daily in 600–700 clubs and private brothels. The extent of other forms of prostitution such as escort agencies and home-based prostitution is much more difficult to estimate. Home-based prostitution occurs in at least 17 municipalities and escort agencies exist in at least 28 municipalities.