The New York City Police Department Housing Bureau is responsible for providing the security and delivery of police services to about 420,000 people using public housing throughout New York City. They are stationed in Police Service Areas (PSA), which are almost identical to police precincts, with nine PSAs in total located throughout the five boroughs. Officers often do vertical patrols, making sure illegal activity does not take place in the halls, stairways, or the roof. The New York City Housing Authority Police Department was merged with the New York City Police Department (NYPD), like the New York City Transit Police, in 1995. Some new police officers are randomly assigned to housing units. Statistics on crimes in NYC Public Housing are posted by the NYCPD and are available on-line at http://www.nyc.gov/html/nypd/downloads/pdf/crime_statistics/hb_eagle_report.pdf