There are many possible causes of homelessness, but this research will focus on the two main reasons: insufficient economic resources and affordable housing. Homelessness is first and foremost a problem of poverty. People who experience homelessness do not have sufficient financial resources to obtain or maintain a livelihood and housing. This includes being unemployed, as well as being underemployed and relying on government benefits that do not cover basic living expenses. Data from the U.S. Census Bureau's 2010 American Community Survey (ACS) show that 75 percent of households at or below the poverty line face severe housing costs. Unexpected financial crises threaten housing stability and can lead to increased risk of homelessness. Poverty remains a significant feature of life in the United States and around the world. In the United States, Census Bureau statistics found that the percentage of Americans below the poverty line in 1959 was 22.4 percent and 11.7 percent in 1973 (down from 11.7 percent ). In 2006, the official poverty rate was 12.3 percent (1.2 percent increase). The question nevertheless remains: what is poverty and how to measure it? Why does the richest country in the world have many people living in poverty? The book Poverty in America: a Handbook by John Iceland is a very informative book on these issues. The book addresses the topic of defining what poverty is and how it is measured. It also provides information on the history of poverty in the United States and how it was perceived then and now, the characteristics of the poor population, the causes of poverty, and the reasons for where the poverty rate is still high. At the end, it examines po......middle of article......2011) Current statistics on the prevalence and characteristics of homeless people in the United States. SAMHSA. Accessed April 2, 2012, from http://homeless.samhsa.gov/ResourceFiles/hrc_factsheet.pdf New York City Mayor's Office, April 2014. “The CEO Poverty Measure, 2005 - 2012: An Annual Report from the Office of the Mayor." Office of the Mayor of New York. Internet. June 20, 2014. The Human Rights Project. (2007). Racial realities in New York. Urban Justice Center. Accessed May 20, 2012 at www.urbanjustice.org/pdf /U.S. Department of Housing and Urban Development (2010) The 2010 Annual Homeless Assessment Report to Congress (6th Report). www.onecpd.info/resources/documents/2010homelessassessmentreport.pdf