Statistics on the Wage of Persons with Disabilities Sampling errors: variation coefficients for the annual earnings per worker variable Type of contract Unidades: coefficient of variation ;Total;Persons without disabilities;Persons with disabilities; Total;0,42;0,43;2,43; Permanent contract;0,54;0,56;2,72; Temporary contract;1;1,02;4,84; Notas: Persons with disabilities refers to persons formally recognised as disabled, with a degree of dissability of 33% or over, according to the procedure for evaluating this established in the RD 1971/1999 and modified by the RD 1856/2009. 2) When the box is marked with a '-' sign before the data, it indicates that the number of sample observations is between 100 and 500, so the figure is subject to great variability. Fuente: Spanish National Statistics Institute