Twenty percent of the work force - 26 million people - earn $8.23 an hour or less.
Of those, 52 percent earned less than they had at their last jobs.
In 1992, 14 percent of the men working full time earned less than $13,091.
Of the total, 73 percent have earned the highest degree in their field.
But 0.5 percent earn more than 10 times the poorest.
Almost 20 percent of the households earn less than $10,000 a year.
In 1910, just 13 percent of those 25 or older had earned high school degrees.
Ten percent of those principals earned more than $230,000, it said.
Last year, only 38 percent of 30,000 students in the nation who took the test earned a 5.
The middle 50 percent earned between $92,670 and $121,310 a year.