Sweden passed a law in 1999 criminalizing the purchase of sex to address prostitution as a form of violence against women. The law aims to reduce demand for prostitution by punishing buyers with fines or up to 1 year in prison. Studies show the number of Swedish men buying sex has decreased since the law's passage, and women in prostitution report fewer buyers. However, critics argue prostitution has just gone underground or moved to other countries. The Stockholm police prostitution unit works to enforce the law through undercover operations that typically result in arresting buyers, pimps and freeing victims.