Q. Where can I find historical and current economic data for countries worldwide?

Go to Euromonitor's Passport GMID.

OECD Economic Outlook : Provides detailed analyses of recent developments in demand, production, employment, prices and wages for OECD member nations and selected non-member countries. Each volume covers an individual country.

For European statistics, go to Eurostat

Also, visit International Macroeconomic Data Set for a time series of GDP, population, etc.