| 年代际 | 久治 | 班玛 | 达日 | 甘德 | 玛多 | 玛沁 | 果洛 |
| 1976~1979 | 24.8 | 21.6 | 22.2 | 19.0 | 15.2 | 20.2 | 20.5 |
| 1980~1989 | 23.1 | 22.0 | 22.8 | 19.1 | 15.3 | 20.0 | 20.5 |
| 1990~1999 | 23.3 | 21.5 | 22.4 | 19.8 | 15.9 | 21.2 | 20.7 |
| 2000~2009 | 22.8 | 21.6 | 21.8 | 20.4 | 15.1 | 20.4 | 20.3 |
| 2010~2018 | 24.2 | 23.5 | 22.0 | 19.4 | 16.8 | 21.2 | 21.2 |
| 1998~2018 | 23.5 | 22.7 | 21.9 | 19.8 | 15.7 | 20.8 | 20.7 |
| 2009~2018 | 24.1 | 23.4 | 22.4 | 19.9 | 16.7 | 21.0 | 21.1 |
| 2014~2018 | 23.7 | 24.1 | 22.4 | 19.9 | 16.8 | 22.1 | 21.2 |
| 1976~2018 | 23.5 | 22.1 | 22.2 | 19.6 | 15.7 | 20.7 | 20.6 |