| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.22 | 2.62 | 1.97 |
| 2024 | 2.01 | 2.44 | 1.61 |
| 2023 | 2.69 | 3.39 | 2.11 |
| 2022 | 2.81 | 3.92 | 1.89 |
| 2021 | 2.81 | 3.59 | 2.17 |
| 2020 | 3.26 | 4.14 | 2.65 |
| 2019 | 3.61 | 6.55 | 1.77 |
| 2018 | 2.31 | 3.48 | 1.75 |
| 2017 | 6.99 | 11.02 | 3.19 |
| 2016 | 8.93 | 11.31 | 6.46 |
| 2015 | 8.52 | 11.41 | 6.51 |
| 2014 | 6.09 | 8.87 | 4.39 |
| 2013 | 3.58 | 4.68 | 2.33 |
| 2012 | 2.48 | 3.4 | 1.79 |
| 2011 | 2.97 | 4.51 | 2.04 |
| 2010 | 3.13 | 5.18 | 1.98 |
| 2009 | 2.19 | 3.11 | 1.15 |
| 2008 | 2.28 | 4.87 | 0.73 |
| 2007 | 4.29 | 6.28 | 3.15 |