Table 1: Sociodemographic characteristics of the sample ( 𝑁 = 7 2 8 ).

Variables 𝑁 %

( 1 ) Sex
 Male29741
 Female43159
( 2 ) Mean age ± SD
 Male32.74 (±5.99)
 Female31.35 (±5.03)
( 3 ) Marital status
 Single22230
 Married50670
( 4 ) Education
 Junior college or vocational school
 equivalency degree
40155
 College graduate or higher32745
( 5 ) Type of job
 Clerical post8111
 Computer technical support63687
 Managerial post112
( 6 ) Shift work
 Without25235
 With47665
( 7 ) Mean working hours per day
 Less than seven or fewer hours per day598
 Eight hours per day38453
 Nine hours per day16122
 Ten hours per day9413
 More than eleven hours per day304
( 8 ) Frequency of working on days off
 Non58180
 More than one day on a monthly basis14720