Try this new beta version search engine, Zanran, which specifically searches for good quality data and statistics: http://www.zanran.com/.
This is what Zanran say about their search engine:
“Zanran helps you to find ‘semi-structured’ data on the web. This is the numerical data that people have presented as graphs and tables and charts. For example, the data could be a graph in a PDF report, or a table in an Excel spreadsheet, or a barchart shown as an image in an HTML page. This huge amount of information can be difficult to find using conventional search engines, which are focused primarily on finding text rather than graphs, tables and bar charts. Put more simply: Zanran is Google for data.”
Remember there are also useful links to scholarly sources of data and statistics on the Swansea University Information Services & Systems website at