After reaching a peak of 442,337 residents counted in the 1930 census, and a post-war population of 438,776 in 1950, the city's population saw a decline of nearly 40% as residents moved to surrounding suburbs. White flight from Newark to the suburbs started in the 1940s and accelerated in the 1960s, due in part to the construction of the Interstate Highway System. The 1967 riots resulted in a significant population loss of the city's middle class, many of them Jewish, which continued from the 1970s through to the 1990s. The city lost about 130,000 residents between 1960 and 1990.