From http://aws.amazon.com/publicdatasets/
“United States demographic data from the 1980 (approximately 2 GB), 1990 (approximately 50 GB), and 2000 US Censuses (approximately 200GB)”
Should we expect a 400GB volume for the 2010 census, or 2TB in 2020 and 200TB in 2040? Probably the latter once you start adding biodata.