General characteristics of the study population
| Variables | n | % |
| Sex | ||
| Male | 4480 | 51.13 |
| Female | 4283 | 48.87 |
| Age | ||
| Younger | 3603 | 55.77 |
| Older | 2858 | 44.23 |
| Education | ||
| College or higher | 592 | 6.75 |
| Secondary | 1129 | 12.88 |
| Primary | 1634 | 18.64 |
| No education, preschool | 5409 | 61.72 |
| Occupation | ||
| Manual | 2142 | 24.89 |
| Non-manual | 6464 | 75.11 |
| Wealth index | ||
| Poorest | 1696 | 19.36 |
| Poorer | 1671 | 19.06 |
| Middle | 1692 | 19.31 |
| Richer | 1784 | 20.35 |
| Richest | 1921 | 21.92 |
| Place of residence | ||
| Rural | 6623 | 75.58 |
| Urban | 2140 | 24.42 |