| Time series | First year | Last year | N | Test Z | Sig | Q |
| ThaPla | 1988 | 2017 | 30 | −0.36 |
| −2.22 |
| Laplae | 1988 | 2017 | 30 | −0.89 |
| −7.78 |
| Fakkai | 1988 | 2017 | 30 | −1.30 |
| −12.76 |
| Ban Khok | 1988 | 2017 | 30 | −1.27 |
| −8.12 |
| Thong Saen Khan | 1988 | 2017 | 30 | −1.03 |
| −10.44 |
| Tambon Tha Pla | 1988 | 2017 | 30 | −2.50 | * | −30.20 |
| Fakara | 1988 | 2017 | 30 | 0.37 |
| 3.37 |
| Huai Mo Mun | 1988 | 2017 | 30 | −1.11 |
| −7.92 |