Is this your guess or is it based on some authoritative source?

来源: 于 2009-09-12 19:14:25 [旧帖] [给我悄悄话] 本文已被阅读：次

What is the source for the claim that the income of the particular group of families is "typically on top 2%~5% among all American Families if both parents are working or on top 10~15% if one is working"?