費了半天勁貼了11張圖,自己沒看懂就亂抒情,唉。。。 看看下麵的數字
Average Pretax household Income (2007 Dollars)
Year Lowest Quintile Second Quintile Middle Quintile Fourth Quintile Highest Quintile
1979 16,600 36,100 54,100 73,200 140,300