15->269 American billionaires in 30 years

In 1982 there were 13 billionaires, in 1983...15; in 1984...12; in 1985...13; in 1986...26; in 1987...49;... 1990...99
Number of Billionaires Per Country Today
America has: 269 (as of 2002 or later????)

To calculate the value of the dollar in a year
I don't understand economics. But here goes!

Current GDP Per Capita By Country U.S. has $37,600 (2002)

Lookie here, What was the GDP In the year ___?
This site says $35,790 for 2003

Now, let's compare 1983 -> 2002 ratio of num billionaires to GDP
1983: 15 / $23,148 (in 2000 dollars)
2002: 269 / $34,937
$55.35 in the year 1983 has the same "purchase power" as $100 in the year 2002

Well, looks like the rich are getting richer.
151% increase in GDP per capita
180% increase in cost of products
so, average person got poorer (i think!)
meanwhile, 15 billionaires -> 269 billionaires
a billion in 1983 was worth about two billion in 2003.
so i'm not sure if this statistic is really saying anything (e.g.how many people had 600million in 1983)

How Much Is That, Economic History Services