Sixty-two percent of its buildings date from 1949 and before, 20 percent were built between 1949 and 1974, and only 18 percent of the buildings remaining were built after that date. Two-thirds of the city's 1.3 million residences are studio and two-room apartments. Paris averages 1.9 people per residence, a number that has remained constant since the 1980s, but it is much less than Île-de-France's 2.33 person-per-residence average. Only 33 percent of principal residence Parisians own their habitation (against 47 percent for the entire Île-de-France): the major part of the city's population is a rent-paying one. Social or public housing represented 19.9 percent of the city's total residences in 2017. Its distribution varies widely throughout the city, from 2.6 percent of the housing in the wealthy 7th arrondissement, to 24 percent in the 20th arrondissement, 26 percent in the 14th arrondissement and 39.9 percent in the 19th arrondissement, on the poorer southwest and northern edges of the city.