> What was the corresponding figure for the EU, or some
> other comparative stat?
According to Eurostat, the EU-27 racked up 11.558 trillion EUR in 2006, US was about 10.550 trillion EUR, roughly a 10% difference. (Note this leaves out Norway and Switzerland, heavily integrated into Eurocapital, which generate another half trillion EUR of output, so it's more like a 15% difference). You can download the charts and numbers from their "Economy and Finance" section here:
Just click on "Gross Domestic Product at Market Prices". Lots of good data on the site.
-- DRR