Shifting proportions between mid pay and low pay jobs

"A recent presentation from the Federal Reserve Bank of San Francisco lays out the situation clearly. The vast majority of job losses during the recession were in middle-income occupations, and they’ve largely been replaced by low-wage jobs since 2010:Mid-wage occupations, paying between $13.83 and $21.13 per hour, made up about 60 percent of the job losses during the recession. But those mid-wage jobs have made up just 27 percent of the jobs gained during the recovery. By contrast, low-wage occupations paying less than $13.83 per hour have utterly dominated the recovery, with 58 percent of the job gains since 2010. (This data all comes from an earlier report (pdf) from the National Employment Law Project.)"