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

All occupations;0.45;
A. Public administration management and management of companies with 10 or more employees;1.91;
B. Management of companies with less than 10 employees;1.23;
D. Professions associated with 2nd and 3rd cycle university degrees and the like;1.29;
E. Professions associated with a 1st cycle university degree and the like;1.12;
F. Support technicians and professionals;1.30;
G. Administrative type employees;0.91;
H. Catering services workers and personal services workers;1.22;
J. Protection and security service workers;4.10;
K. Retail workers and the like;1.66;
L. Workers skilled in agriculture and fishing;3.73;
M. Skilled  construction workers, except machinery operators;2.06;
N. Skilled extractive industry workers, metallurgy, construction, machinery and related trades workers;1.09;
P. Skilled workers from the graphic arts, textile and preparation, elaboration of food, cabinetmakers, craftspersons and other similar industries;1.31;
Q. Fixed machinery and industrial installation operators fitters and assemblers;0.77;
R. Mobile machinery drivers and operators;1.48;
S. Unskilled service workers (except transport);1.27;
T. Agriculture, fishing, construction, manufacturing and transport labourers;1.47;
Notes:
Source: National Statistics Institute