One limited measure of the growth in homelessness is the increase in the number of shelter beds over time. A 1991 study examined homelessness "rates" (the number of shelter beds in a city divided by the city's population) in 182 U.S. cities with populations over 100,000. The study found that homelessness rates tripled between 1981 and 1989 for the 182 cities as a group (Burt, 1997).
A 1997 review of research conducted over the past decade (1987-1997) in 11 communities and 4 states found that shelter capacity more than doubled in 9 communities and 3 states during that time period (National Coalition for the Homeless, 1997). In two communities and two states, shelter capacity tripled over the decade.
These numbers are useful for measuring the growth in demand for shelter beds (and the resources made available to respond to that growth) over time. They indicate a dramatic increase in homelessness in the United States over the past two decades. Additionally, in the U.S. Conference of Mayors report from 2007, 15 of the 23 cities surveyed stated that they believed numbers would continue to increase in 2008.
Read more on the homeless here.