Tax expenditures are projections of the lost revenue of all special federal tax measures designed to support the economic and social priorities of the Government and they include things like donation tax credits, GST rebates for charities etc.  Here is the 2009 report.  Remember there are a lot of caveats with these numbers including but not limited to these are the federal costs (not provincial, municipal costs), in some cases hospital and universities are treated separately from registered charities.

Here is the link: