Twenty20 Bowling in Each Season by Fred Klaassen
| Season | | Balls | Mdns | Runs | Wkts | BB | Ave | 4wI | 5wI | SRate | Econ |
| 2018 | (England) | 12 | 0 | 12 | 1 | 1-12 | 12.00 | 0 | 0 | 12.00 | 6.00 |
| 2018 | (Netherlands) | 96 | 0 | 151 | 3 | 1-29 | 50.33 | 0 | 0 | 32.00 | 9.43 |
| 2018-19 | (Oman) | 72 | 0 | 95 | 6 | 3-31 | 15.83 | 0 | 0 | 12.00 | 7.91 |
| 2019 | (Ireland) | 62 | 0 | 108 | 0 | | | | | | 10.45 |
| 2019 | (Netherlands) | 47 | 0 | 64 | 3 | 3-36 | 21.33 | 0 | 0 | 15.66 | 8.17 |
| 2019 | (England) | 247 | 0 | 384 | 10 | 2-24 | 38.40 | 0 | 0 | 24.70 | 9.32 |
| 2019-20 | (Oman) | 54 | 0 | 72 | 1 | 1-29 | 72.00 | 0 | 0 | 54.00 | 8.00 |
| 2019-20 | (Pakistan) | 48 | 0 | 64 | 3 | 2-41 | 21.33 | 0 | 0 | 16.00 | 8.00 |
| 2019-20 | (United Arab Emirates) | 84 | 0 | 91 | 7 | 2-7 | 13.00 | 0 | 0 | 12.00 | 6.50 |
| 2020 | (England) | 244 | 0 | 374 | 13 | 3-36 | 28.76 | 0 | 0 | 18.76 | 9.19 |
| 2021 | (England) | 309 | 0 | 456 | 24 | 4-17 | 19.00 | 2 | 0 | 12.87 | 8.85 |
| 2021-22 | (United Arab Emirates) | 55 | 0 | 44 | 2 | 1-14 | 22.00 | 0 | 0 | 27.50 | 4.80 |
| 2022 | (Zimbabwe) | 112 | 0 | 122 | 10 | 5-19 | 12.20 | 0 | 1 | 11.20 | 6.53 |
| 2022 | (England) | 341 | 2 | 521 | 14 | 2-26 | 37.21 | 0 | 0 | 24.35 | 9.16 |
| 2022-23 | (Australia) | 180 | 0 | 191 | 8 | 2-13 | 23.87 | 0 | 0 | 22.50 | 6.36 |
| 2023 | (England) | 114 | 1 | 145 | 7 | 2-31 | 20.71 | 0 | 0 | 16.28 | 7.63 |
| 2023-24 | (Nepal) | 42 | 0 | 70 | 3 | 2-37 | 23.33 | 0 | 0 | 14.00 | 10.00 |