| Certification | Grade | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | Total | Rate (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Preliminary certification | Best | 0 | 0 | 1 | 1 | 0 | 1 | 4 | 0 | 7 | 3.1% |
| Good | 1 | 7 | 12 | 27 | 26 | 40 | 65 | 37 | 215 | 96.4% | |
| Normal | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0.4% | |
| Certification | Best | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0.4% |
| Good | 0 | 1 | 7 | 26 | 33 | 58 | 50 | 39 | 214 | 89.2% | |
| Normal | 0 | 0 | 0 | 4 | 14 | 1 | 6 | 0 | 25 | 10.4% | |
| Total | 1 | 8 | 20 | 59 | 73 | 101 | 125 | 76 | 463 | ||