Who knows what "rich" means. Obviously a personal thing. Why does it matter? As long as you have enough for your lifestyle? Seems to me that the term "rich" has taken on a negative connotation anyway. I much prefer the terms well off, comfortable, set, or even better just plain "lucky".
Most references to "Rich" are as "High Net Worth Individuals"
(Wikipedia)
A
high net worth individual (
HNWI) is a person with a high
net worth. In the
private banking business, these individuals typically are defined as having investable assets (financial assets not including primary residence) in excess of US$1 million.
(SEC)
The
U.S. Securities and Exchange Commission requires all SEC-registered investment advisers to periodically file a report known as Form ADV.
[6] Among other things, Form ADV requires each investment adviser to state how many of his clients are
"high net worth individuals." The Form ADV Glossary of Terms explains that a
"high net worth individual" is an individual with at least $750,000 managed by the reporting investment adviser, or whose net worth the investment adviser reasonably believes exceeds $1,500,000 (or who is a "qualified purchaser" as defined in section 2(a)(51)(A) of the Investment Company Act of 1940). The net worth of an individual for SEC purposes may include assets held jointly with his or her spouse. Unlike the definitions used in the financial and banking trade, the SEC's definition of HNWI would include the value of a person's verifiable non-financial assets, such as a primary residence or art collection.
The World Wealth Report 2010 shows the US having 1% HNWIs:
World Wealth Report 2010 Pdf Free Ebooks (pdf , doc , xls and etc.)
(PDF of report is too large to attach)
EDIT: (should be easier source for report)
http://www.trigoncapital.com/upload/wealth_managment/TWM/World_Wealth_Report_2010.pdf
If you go by the above criteria: Rich = HNWIs (which are those with investable assets of $1M or greater). Maybe that roughly 1% (+/- 2.9M) of the total US population that are classified as HNWIs don't view themselves as "Rich", but would guess the other 99% most likely do.