H1: National income accounting websites

Economic Survey of Singapore 2007
http://app.mti.gov.sg/data/article/12381/doc/ESS_2007Ann_Full_Report.pdf

Human Development Index
http://hdr.undp.org/en/statistics/

Big Mac Index
http://www.economist.com/finance/displaystory.cfm?story_id=11793125

Happy exploring!

H1: Roman Empire's GDP?

Angus Maddison is like the Sherlock Holmes for compiling world economies statistics on long time horizons, since the year 1AD. He explains how you can work out the GDP of the Roman Empire (going back to the average of gold & wheat units) as well as GDP of China (technologically more advanced in 1000AD, but fell behind after Europe's scientific revolution in the 1500s).
Listen to his interview with BBC here:
http://news.bbc.co.uk/today/hi/today/newsid_7516000/7516994.stm