percentage of workers with "good jobs" -- earning at least $37,000 a year with benefits -- fell to 24.6 in 2010, from 27.4 in 1979. That's a drop-off of roughly half a million workers. And while low-paying and temp jobs have also been growing over that same time period, the number of temp jobs has exploded since the recession began in 2009. According to statistics provided by the Bureau of Labor Statistics, the number of temp jobs have risen 50 percent over the past for years and now total 2.7 million. "Hundreds of thousands of workers have a standard of living that's lower than what their parents had thirty years earlier," observes Chris Owens, the executive director for the National Employment Law Project. As the CEPR report notes, workers of all ages and educational status are finding it harder to secure good, full-time positions with benefits. Three factors appear to be at play for why more Americans are stuck in crappy jobs: 1. Companies organize work around "projects." That means less hiring and a greater reliance on temp staff. The top companies of the Standard & Poor 500 have doubled their profits since 2009. Yet while companies may be thriving, workers and their wages are stuck in a holding pattern. Unemployment has remained above 7.5 percent and salaries have been stagnant. Companies are upfront about getting ahead with less. "In good times, companies can just throw people at the problem," Peter Bauer, the CEO of Mimecast, a Mass.-based firm that helps other companies manager their e-mail systems, recently told CNN Money. "But in lean times, you pay a lot more attention to efficiency." Since the firm opened its offices in Watertown, Mass., it has cut its sales department by a quarter, helping it save $2.7 million a year. The consequences of all the belt-tightening for workers can be seen in the growth of freelance workers. The Freelancers' Union estimates one in three American workers, or 42 million Americans now work as "free agents," which means their employer doesn't provide them with benefits or full-pay. 2. New technology disrupts industries and make jobs obsolete. In a highly-cited study conducted last year by the Economist Intelligence Unit (EIU) of 567 global executives, 60 percent said their industry will "bear little resemblance in 2020 to how it looks today." The cause? Technological changes will make certain jobs obsolete and force separate occupations to merge into one profession. The executives expect convergence to occur in banking and telecommunications, to take one example. That development will force workers in those fields to adapt to a new line of work in order to stay afloat.