Table 1.
Characteristics of the sample: 2004, 2009, and 2014.
| 2004 | 2009 | 2014 | ||||
|---|---|---|---|---|---|---|
| (n = 27,596) | (n = 18,412) | (n = 24,670) | ||||
| Men | Women | Men | Women | Men | Women | |
| Sleep Time (minutes) | 466.76 | 451.23 | 465.71 | 458.48 | 471.63 | 462.71 |
| Continuous variable | ||||||
| Age | 45.81 | 45.8 | 46.26 | 46.02 | 47.35 | 47.16 |
| Domestic work (minutes) | 33.53 | 223.37 | 36.72 | 210.89 | 42.08 | 204.93 |
| Care work (minutes) | 15.52 | 44.16 | 18.37 | 54.04 | 18.04 | 47.02 |
| Income level (range: 1–11) | 4.16 | 1.26 | 6.11 | 2.80 | 7.31 | 3.61 |
| Categorical variable (%) | ||||||
| Day of week | ||||||
| weekdays | 60.21 | 60.20 | 59.74 | 59.98 | 59.89 | 60.07 |
| Saturday | 19.84 | 19.95 | 20.10 | 20.03 | 19.85 | 19.79 |
| Sunday | 19.94 | 19.85 | 20.16 | 19.99 | 20.26 | 20.15 |
| Education | ||||||
| middle school and less | 24.14 | 41.80 | 17.36 | 28.99 | 12.31 | 18.90 |
| high school | 44.90 | 43.20 | 45.35 | 48.38 | 41.25 | 46.41 |
| some college | 5.62 | 3.87 | 11.52 | 9.08 | 14.35 | 14.33 |
| above university | 35.34 | 11.13 | 25.78 | 13.54 | 32.08 | 20.36 |
| Urban/rural | ||||||
| rural | 9.06 | 9.48 | 5.51 | 5.82 | 5.72 | 5.60 |
| urban | 90.94 | 90.52 | 94.49 | 94.18 | 94.28 | 94.4 |
| Marital status | ||||||
| single | 5.03 | 1.75 | 6.18 | 2.48 | 8.58 | 4.18 |
| with spouse | 94.97 | 98.25 | 93.82 | 97.52 | 91.42 | 95.82 |
| Employment status | ||||||
| not employed | 9.76 | 38.82 | 8.73 | 39.68 | 7.60 | 37.91 |
| employed | 90.24 | 61.18 | 91.27 | 60.32 | 92.40 | 62.09 |
| Those who overworked | 41.40 | 24.21 | 40.62 | 20.42 | 33.84 | 15.30 |
| Those who have child less than age 10 | 29.97 | 22.32 | 25.53 | 19.70 | 26.66 | 21.63 |
| Those who feel time pressed | 83.01 | 64.10 | 77.35 | 73.68 | 68.17 | 62.76 |
| Those who have gender equal attitudes | 44.72 | 60.26 | 49.78 | 63.62 | 52.60 | 71.01 |
| Those who have few free time | 21.71 | 24.88 | 23.47 | 26.90 | 28.56 | 28.24 |
Note: We tested the difference of sleep time, domestic work time and care work time between middle aged men and women. The differences between men and women were statistically significant at 0.01 level without controls. More robust statistical significance test of the gender difference in sleep time with controls is shown in Table 2.