 Since the decline of working class blue-collar jobs in manufacturing and industry, younger native-born generations have acquired higher education.In the US, only 12% of the labor force has less than a high school education, but 70% of illegal workers from Mexico lack a high school degree.The majority of new blue-collar jobs qualify as Massey's "underclass" work, and suffer from unreliability, subservient roles and, critically, a lack of potential for advancement.