| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.47 | 1.94 | 1.23 |
| 2024 | 1.06 | 1.63 | 0.8 |
| 2023 | 0.96 | 1.06 | 0.85 |
| 2022 | 0.87 | 1.12 | 0.7 |
| 2021 | 0.81 | 1.03 | 0.66 |
| 2020 | 1 | 1.24 | 0.88 |
| 2019 | 0.55 | 1.19 | 0.4 |
| 2018 | 0.53 | 0.7 | 0.38 |
| 2017 | 1.67 | 3.28 | 0.64 |
| 2016 | 2.79 | 3.49 | 2.41 |
| 2015 | 3.42 | 4.74 | 2.01 |
| 2014 | 2.59 | 3.95 | 1.77 |
| 2013 | 1.6 | 2.21 | 1.18 |
| 2012 | 1.6 | 1.9 | 1.31 |
| 2011 | 3.22 | 6.97 | 1.42 |
| 2010 | 5.73 | 8.27 | 4.05 |
| 2009 | 3.86 | 5.64 | 2.47 |
| 2008 | 5.16 | 9.61 | 1.82 |
| 2007 | 8.21 | 13.29 | 3.9 |
| 2006 | 3.96 | 5.28 | 3.29 |
| 2005 | 4.31 | 6.43 | 3.17 |
| 2004 | 8.62 | 17.2 | 4.69 |