| Scale | Type | Time | Mean (cm) | Variance (cm2) | p |
| Province | Whole | 1980s | 16.3a | 6.8 | 0.015 |
| 2010s | 17.4b | 9.7 | |||
| North | 1980s | 16.8a | 6.3 | 0.003 | |
| 2010s | 19.1b | 8.1 | |||
| Middle | 1980s | 15.8a | 4.9 | 0.529 | |
| 2010s | 16.2a | 5.9 | |||
| South | 1980s | 16.3a | 8.9 | 0.432 | |
| 2010s | 17.0a | 11.1 | |||
| Dry-land | 1980s | 17.4a | 6.8 | 0.022 | |
| 2010s | 18.8b | 6.9 | |||
| Paddy-field | 1980s | 15.3a | 4.9 | 0.140 | |
| 2010s | 16.1a | 9.0 | |||
| County | Mengcheng (North) | 1980s | 16.8a | 1.1 | 0.003 |
| 2010s | 14.8b | 8.0 | |||
| Dingyuan (Middle) | 1980s | 14.7a | 3.6 | 0.631 | |
| 2010s | 15.0a | 8.3 | |||
| Xuanzhou (South) | 1980s | 13.7c | 11.5 | 0.000 | |
| 2010s | 16.9d | 2.7 | |||
| County sum. | 1980s | 15.0a | 6.8 | 0.314 | |
| 2010s | 15.5a | 7.0 |