Four-yearly Wage Structure Survey 
Sample errors
Variation coefficients for the gross annual earnings by main groups of the NCO-94
Units: %

All occupations;0.40;
A. Public administration management and management of companies with 10 or more employees;3.00;
D. Professions associated with 2nd and 3rd cycle university degrees and the like;2.60;
E. Professions associated with a 1st cycle university degree and the like;1.40;
F. Support technicians and professionals;1.30;
G. Administrative type employees;1.00;
H. Catering services workers and personal services workers;1.30;
J. Protection and security service workers;1.90;
K. Retail workers and the like;1.70;
L. Workers skilled in agriculture and fishing;4.80;
M. Skilled  construction workers, except machinery operators;1.30;
N. Skilled extractive industry workers, metallurgy, construction, machinery and related trades workers;1.10;
P. Skilled workers from the graphic arts, textile and preparation, elaboration of food, cabinetmakers, craftspersons and other similar industries;1.70;
Q. Fixed machinery and industrial installation operators fitters and assemblers;0.70;
R. Mobile machinery drivers and operators;1.20;
S. Unskilled service workers (except transport);1.10;
T. Agriculture, fishing, construction, manufacturing and transport labourers;0.90;
Notes:
Source: National Statistics Institute