Here are some complete, off the top of my head guesses about sme data:
Percentage of people who are “black” on the 1990 Census
Total egg production in 1965 (number of eggs)
560 Million +_100 Million
Number of airline passengers killed in plane crashes in 1980 worldwide
Percentage of babies born in the US that are girls
Percentage of entering college freshman whose probable field of study was physical sciences (1990)
Number of people who watched the 1995 Super Bowl
50 Million +-20 Million
Number of native French speakers in Canada in 1992
10 Million +-5 Million
Number of babies born in the US in 1992
2 Million, +- 1 million
number of abortions in the US in 1992
1 million, +- 50 Thousand
median household income in the US in 1996
40,000, +-20 Thousand
And here are some ideas for data-related projects!
Compare an food bills from before and after NYC instituted the mandatory calorie labeling laws.
Use long-term savings numbers to chart off milestones in your life
How much do people pay in health insurance, vs. how many times a year someone sees a doctor.
Pick a social network and calculate the most common topics posted on.
What are the most searched for topics on a news site, and what are the most reported on topics.
Use output from itunes, Pandora, music folder dates, or other music listening site to tabulate your moods.