Table 1 Characteristics of respondents (N = 1000)
| Â | N | % |
|---|---|---|
Gender | ||
 Men | 504 | 50.4 |
 Women | 496 | 49.6 |
Education | ||
 University/graduate school graduate | 589 | 58.9 |
 Vocational school/college graduate | 221 | 22.1 |
 High school graduate | 179 | 17.9 |
 Junior high school graduate | 8 | 0.8 |
 Others | 3 | 0.3 |
Marital status | ||
 Unmarried | 319 | 31.9 |
 Married | 576 | 57.6 |
 Divorce | 93 | 9.3 |
 Bereavement | 12 | 1.2 |
Number of child(ren) | ||
 0 | 467 | 46.7 |
 1 | 150 | 15.0 |
 2 | 277 | 27.7 |
 3 | 97 | 9.7 |
 4 | 9 | 0.9 |
Occupations | ||
 Managers | 181 | 18.1 |
 Non-manual workers | 674 | 67.4 |
 Manual workers | 68 | 6.8 |
 Others | 77 | 7.7 |
Night shift | ||
 Yes | 139 | 13.9 |
 No | 861 | 86.1 |