The anti-SRO policies of 1955 were introduced when the demographics of SRO residents changed towards immigrant families; in an environment influenced by "varying degrees of xenophobia and racism", the city took steps to ban new SRO unit construction, prevent families from living in SROs, and change building codes and zoning to discourage SROs. In the 1970s, the city introduced tax incentives for landlords to encourage them to convert SROs into regular apartments, a program which from 1976 to 1981 eliminated two thirds of the SRO stock in the city.