SROs are a form of affordable housing, in some cases for formerly or otherwise homeless individuals. SRO units are the least expensive form of non-subsidized rental housing, with median rents even in New York City ranging from $450 to $705 per month. The term is primarily used in Canada and US. Since the 1970s and 1980s, there has been an increasing displacement of SRO units aimed at low-income earners due to gentrification, with SRO facilities being sold and turned into condominiums. Between 1955 and 2013, almost one million SRO units were eliminated in the US due to regulation, conversion or demolition.