Often the single best starting-point for finding statistics on education (or nearly anything else) is the Statistical Abstract of the United States, which has been published annually by the U.S. Census Bureau.

However, the most comprehensive collection of education-related statistics is the National Center for Education Statistics, an agency within the U.S. Department of Education. 

Three databases you can use to find publications from the U.S. Federal Government:

Federal Government Watchdog Agencies

Congressional Research Service, Congressional Budget Office, etc.

ProQuest Congressional

Access to nearly every document created by Congress, including committee hearings. 

Catalog of U.S. Government Publications

Over 1/2 million entries for electronic and print publications from Federal Government agencies.