Dennis P. Culhane’s “path-breaking” study of turnover rates in shelters in New York City and Philadelphia, which produced an unduplicated count of the actual number of homeless people in city shelter systems over a period of time, revealed that three percent of Philadelphia’s population used the public shelter system between 1990 and 1992, and that three percent of New York’s population received shelter during the same period. The work of Culhane’s and others conclusively demonstrated that homelessness was a much more widespread problem than the government had previously acknowledged. A recent study now estimates that between 700,000 to 800,000 people are homeless each night and that between 2.3 to 3.5 million people are homeless each year.