| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.28 | 1.52 | 1.12 |
| 2024 | 1.23 | 1.79 | 0.84 |
| 2023 | 1.17 | 1.4 | 0.95 |
| 2022 | 1.14 | 1.66 | 0.71 |
| 2021 | 1.54 | 2.23 | 1.28 |
| 2020 | 1.48 | 1.71 | 1.19 |
| 2019 | 1.83 | 2.54 | 1.3 |
| 2018 | 2.27 | 3.43 | 1.52 |
| 2017 | 3.98 | 5.34 | 2.91 |
| 2016 | 4.21 | 5.99 | 2.96 |
| 2015 | 4.6 | 7.01 | 2.73 |
| 2014 | 2.99 | 3.92 | 2.32 |
| 2013 | 3.59 | 4.86 | 2.52 |
| 2012 | 3.57 | 5.91 | 2.13 |
| 2011 | 10.04 | 16.76 | 5.34 |
| 2010 | 11.46 | 16.98 | 8.8 |
| 2009 | 7.44 | 10.62 | 4.01 |
| 2008 | 8.58 | 16.17 | 3.07 |
| 2007 | 12.77 | 16.18 | 9.66 |