[Straight Vermonter]

I found similar numbers here that say they are calculated in constant 1999 dollars.

[xzins]

I hand jammed the annual inflation rates from 1980-1992.

The average was 4.065217391

We'll call that 4.07.

If I had 21500 dollars in 1980 I'd better have 52559 bucks in 2002 to say that I had stayed the same. That's 2.44 times higher to stay up with inflation.

The relationship of 21500 to 36000 is only 1.67 times.

A dollar had to grow 2.44 times in that time span to stay up with inflation. They're reporting in this article that the GDP dollar did not grow that much.

Whatever the reason for it, you lost per capita gdp value.

Whatever the reason for it (illegal immigration perhaps), your per capita "American" had more purchasing power in 1980 than in 2002.