This is the Statistical Office of the European Communities, providing freely accessible EU statistics. Access to microdata available with the submission of a research proposal. Microdata are the units of data that aggregate statistics are compiled from. Full details for applying for access availablehere
The Google Public Data Explorer aims to make large, public-interest datasets easy to explore, visualize and communicate. Datasets covered are limited but include World Development Indicators (World Bank), Human Development Indicators (UN) and OECD Factbook.
Although not completely authoritative, the easy user interface will take you quickly to informative data. Sources for all facts and figures are cited. Most statistics come from international agencies, such as U.S. Census Bureau and UNESCO.
The OECD collects statistics needed for the analysis of economic and social developments by its in-house analysts, committees, working parties, and member country governments from statistical agencies and other institutions of its member countries.
Cross-national surveys typically refer to studies where the same survey instrument is used across many nations. Includes: Eurobarometer Surveys, European Election Study and International Social Survey Programme.