 Contrary to that notion, however, sociologists and economists have concluded that, although exceptions are heard of, social mobility has remained stagnant and even decreased over the past thirty years.From 1979 through 2007 the wage income for lower and middle class citizens has risen by less than 17 percent while the one percent has grown by approximately 156 percent sharply contrasting the "postwar period up through the 1970s, when income growth was broadly shared".Some of the decrease in social mobility may be explained by the stratified educational system.