Income PER PERSON is different than PER HOUSEHOLD.
In the US - average income per person (I assume 18 and older - don't want the two year olds to screw up the averages - lazy babies) is about 23K
Average HouseHold Income for 2000 breaks down like this:
10th percentile upper limit . . 10,600
20th percentile upper limit . . 17,950
50th (median) . . . . . . . . . . . . . 42,148
80th percentile upper limit . . 81,960
90th percentile upper limit . . 111,602
95th percentile lower limit. . . 145,526
from
http://www.census.gov/prod/2001pubs/p60-213.pdf