看看美国的统计数据吧。
PA：1999
收入
Less than $10,000 466K 9.7%
$10,000-$14,999 333K 7.0%
$15,000-$24,999 657K 13.8%
$25,000-$34,999 634K 13.3%
$35,000-$49,999 809K 16.9%
$50,000-$74,999 930K 19.5%
$75,000-$99,999 457K 9.6%
$100,000-$149,999 317K 6.6%
$150,000-$199,999 84173 1.8%
$200,000 or more 90874 1.9
教育
Less than 9th grade 452K 5.5%
9th to 12th, no diploma 1.04M 12.6%
High school graduate 3.15M 38.1%
Some college, no degree 1.28M 15.5%
Associate degree 488K 5.9%
Bachelor degree 1.15M 14.0%
Graduate or prof. degree 694K 8.4%
High school or more 6.77M 81.9%
Bachelor degree or more 1.85M 22.4%
