By Doug Cunningham

The percentage of hourly workers earning at least $20 an hour in the U.S. is down to just 16 percent. In 1979 it was 23 percent, according to the Bureau of Labor Statistics. That middle-class blue collar wage is essential to sustaining America’s middle class. The hourly wage decline is the worst in manufacturing, which is seeing a 60 percent drop in the number of workers earning at least $20 an hour.