Employee Benefits in the United States, March 2018

Footnotes:
(1) The sampling frame was developed from state unemployment insurance reports and is based on the 2012 North American Industry Classification System (NAICS). With some minor exceptions, an establishment is a single economic unit that engages in one, or predominantly one, type of economic activity. For private industry, the establishment is usually at a single physical location such as a mine, factory, office, or store; if a sampled establishment is owned by a larger entity with many locations, only the employment and characteristics of the establishment selected for the sample are considered for the survey. For state and local governments, an establishment can include more than one physical location, such as a school district or a police department.
(2) Establishments that provided data at the initial interview.
(3) Establishments that did not provide data at the initial interview. Data for establishments not responding at the time of update interviews are imputed. For information on nonresponse adjustment and imputation, see "National Compensation Measures," BLS Handbook of Methods available at www.bls.gov/opub/hom/ncs/home.htm.