What is the percentage of children under age 5 in the fifty states of
the U.S. (You can leave out Puerto Rico, the Virgin Islands, etc.) 
I'd like the most recent figure available, and please tell me for
which year the answer accounts.

Hi! Thanks for the question.

The latest figures from the US Census website are in 2000. These are
the population figures for those under 5 years old per state. In order
to see the original table you have to search in the US Census
Factfinder website. Go to the following link:

http://factfinder.census.gov/servlet/DatasetMainPageServlet?_ds_name=DEC_2000_SF1_U&_program=DEC&_lang=en

Then choose quick tables and choose a table per state or every state.
To save you the trouble I have presented the data you wanted here.

State           Population           Percentage of Population in the
State
                (Under 5 yrs. old)

Alabama -          295,992                         6.7%
Alaska -            47,591                         7.6%
Arizona -          382,386                         7.5%
Arkansas -         181,585                         6.8%
California -     2,486,981                         7.3%
Colorado -         297,505                         6.9%
Connecticut -      223,344                         6.6%
Delaware -          51,531                         6.6%
D.C. -              32,536                         5.7%
Florida -          945,823                         5.9%
Georgia -          595,150                         7.3%
Hawaii -            78,163                         6.5%
Idaho -             97,643                         7.5%
Illinois -         876,549                         7.1%
Indiana -          423,215                         7.0%
Iowa -             188,413                         6.4%
Kansas -           188,708                         7.0%
Kentucky -         265,901                         6.6%
Louisiana -        317,392                         7.1%
Maine -             70,726                         5.5%
Maryland -         353,393                         6.7%
Massachusetts -    397,268                         6.3%
Michigan -         672,005                         6.8%
Minnesota -        329,594                         6.7%
Mississippi -      204,364                         7.2%
Missouri -         369,898                         6.6%
Montana -           54,869                         6.1%
Nebraska -         117,048                         6.8%
Nevada -           145,817                         7.3%
New Hampshire -     75,685                         6.1%
New Jersey -       563,785                         6.7%
New Mexico -       130,628                         7.2%
New York -       1,239,417                         6.5%
North Carolina -   539,509                         6.7%
North Dakota -      39,400                         6.1% 
Ohio -             754,930                         6.6%
Oklahoma -         236,353                         6.8%
Oregon -           223,005                         6.5%
Pennsylvania -     727,804                         5.9%
Rhode Island -      63,896                         6.1%
South Carolina -   264,679                         6.6%
South Dakota -      51,069                         6.8%
Tennessee -        374,880                         6.6%
Texas -          1,624,628                         7.8%
Utah -             209,378                         9.4%
Vermont -           33,989                         5.6%
Virginia -         461,982                         6.5%
Washington -       394,306                         6.7%
West Virginia -    101,805                         5.6%
Wisconsin -        342,340                         6.4%
Wyoming -           30,940                         6.3%
 
Search strategy:
Search for data on the US FactFinder Website
http://factfinder.census.gov/servlet/BasicFactsServlet 

I hope this would help you in your research. Before rating this
answer, please ask for a clarification if you have a question or if
you would need further information.

Thanks for visiting us.

Regards,
Easterangel-ga

Thanks very much.  I find the census factfinder website very difficult
to use and appreciate your time.