Sources for Federal Employee Data | Library of Congress Research Guide
Snippet of Article: "...The content on this page is concerned with the current and historical sources for federal employee salaries. While we have included salaries for some very specific agencies that are often treated independently, we haven't included every instance. For anyone needing to look at the history, responsibility for publishing and publication of the data has changed hands and we have tried to capture those changes. Before the OPM, there was the U.S. Civil Service Commission and others including GAO (General Accounting Office, later renamed General Accountability Office), Census Bureau, Department of Interior, etc. Also, much of the current data will not cover specific people but historically, some sources did report the salaries for named individuals. For anyone looking for current information or data from the..."
Source: guides.loc.gov