| Variables | Category | Number of respondents | Percentage (%) |
| Work type | Framework | 87 | 33.1 |
| Finishing work | 83 | 31.6 | |
| Electricity, machine | 64 | 24.3 | |
| Other | 22 | 8.4 | |
| Career | Less than 5 years | 86 | 32.7 |
| 5 - 10 years | 64 | 24.3 | |
| More than 10 years | 106 | 40.3 | |
| Nationality | Korea | 233 | 88.6 |
| China | 23 | 8.7 |