A survey of employersÂ’ payrolls during the third month of each quarter. It is a probability sample of about 3,600 private companies and 700 public employers, such as government agencies and school systems. Sub- categories include information broken down into white-collar and blue-collar professions, goods and services industries, and benefit information for each of those subgroups. The index also has data categorized by region. The index is released quarterly by the federal Labor DepartmentÂ’s Bureau of Labor Statistics and is widely watched by the financial markets to catch any signs of wage-driven inflation.