The data collection for the surveys on the structure of earnings was conducted in 1966, 1972, 1974, 1978, 1986, 1992, 1994 and 2002. They happen to be less frequent than the surveys on labor costs with which they were frequently matched. These surveys vary a great lot, both by their statistical characteristics (sample size, survey scope, questioning) and by the type of design (questioning mode, two surveys conducted in pairs or independently, etc.). From 1994 until 2002, no investigation of the structure of earnings were conducted. These surveys are ruled by two European regulations. The schedule for the ECMO and ESS surveys is regulated by n° 530/199, dated March 9, 1999. These two surveys are conducted every four years, with a rotation every two years. The n° 1916/2000 European regulation, dated September 8, 2000, provides the list of variables requested by Eurostat, specifying whether or not they are mandatory. Variables may relate not only to the establishment or to employees, but also to the company or to the group in which the establishment is incorporated. Variables concerning employees pertain to three main themes: identification, individual characteristics, compensation elements. In France, INSEE also collects data concerning wage factors such as age of education completion or career breaks.