Insee calculates an index of the hourly cost of labour for all employees, a gross hourly wage index and an index of employers' contributions based on the Survey of Labour Activity and Conditions of Employment (Acemo) and social security contributions.
The hourly labour cost index is a constant structure index, that is, it measures the cost of labour without taking into account possible changes in job qualifications.
It is non-revisable.
It is mainly used in contract escalation clauses.

Four sectors of NACE Rev. 1;
- mechanical and electrical industries (NAF28 to 35);
- the clothing and leather industries (NAF18-19);
- textile industries (NAF17);
- services supplied mainly to enterprises (NAF74).

1997