According to the US Census Bureau, the number of persons living below
the poverty line in 1990 was 33.6m (13.5% of the population); and in
2000 it was 32.3m (11.8% of the population); what are the current
figures?

You can find the latest Census Bureau figures here:

http://www.census.gov/hhes/income/income03/prs04asc.html

PRESS BRIEFING ON 
2003 INCOME AND POVERTY ESTIMATES
FROM THE CURRENT POPULATION SURVEY

Dr. Daniel H. Weinberg
August 26, 2004



...The official poverty rate rose, from 12.1 percent in 2002 to 12.5
percent in 2003. The number in poverty increased also, by 1.3 million
people, to 35.9 million in 2003...


Note that the 2003 data was made public in August 2004, so I imagine
the 2004 update will appear around August of this year.


I trust this information fully answers your question.  However, please
don't rate this answer until you have everything you need.  If you
would like any additional information, just post a Request for
Clarification to let me know how I can assist you further, and I'm at
your service.

All the best,

pafalafa-ga


search strategy:  Google search on [ census poverty ]

Try looking at this National Center for Health Statistics 2004 report:
www.cdc.gov/nchs/data/hus/hus04acc.pdf . On page 7 (pdf page 14 of
25):

"In 2002 the overall percent of Americans living in poverty was 12.1
percent, up from 11.7 percent in 2001 and 11.3 percent in 2000, the
first increase in the poverty rate since 1993. In 2002 more than
one-half of black and Hispanic children under 18 years and more than
one-half of the black and Hispanic population age 65 years and over
were either poor or near poor(figures 4 and 5 and table 2)."

For other information that might be useful for you, look at
http://www.cdc.gov/nchs/hus.htm .