An updated version (August 2015) of a U.S. federal government report (prepared by the Federal Research Division, Library of Congress) that shares a lot of interesting data (including many charts) about government spending on information services and products (not just by libraries) was recently made available and is now embedded at the bottom of this post. The report also includes forecasts of spending through FY 2017.
The complete title of the report is: Federal Government Strategic Sourcing Of Information Products And Services: A Report Prepared by the Federal Research Division, Library of Congress Under an Agreement with the Federal Library and Information Network (FEDLINK), Library of Congress (July 2015)
Direct to Full Text Report
Previous Versions of Report