CareerOneStop
Salary information comes from the Bureau of Labor Statistics, Occupational Employment Statistics Program, a semi-annual survey that provides wage and employment statistics for the nation, each state, and sub-state regions.
The National Compensation Survey
The National Compensation Survey produces quarterly indexes measuring change over time in labor cost, Employment Cost Index (ECI), and quarterly data measuring level of average costs per hour worked, Employer Cost for Employee Compensation (ECEC).
FreeERISA (BenefitsPro)
Free access to all form 5500s filed with the Department of Labors, which include data on retirement, health, life, and other benefits plans from more than 1 million U.S. companies.
Overview of BLS Statistics on Pay and Benfits
BLS data on pay and benefits are available for occupations, industries, geographic areas, and the demographic characteristics of workers.
Savings Matter - US Department of Labor
Employee Benefit Research Institute (EBRI)