| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.99 | 1.11 | 0.87 |
| 2024 | 0.98 | 1.36 | 0.7 |
| 2023 | 1.29 | 1.39 | 1.13 |
| 2022 | 1.5 | 2.09 | 1.24 |
| 2021 | 1.83 | 2.64 | 1.35 |
| 2020 | 1.57 | 2.88 | 1.28 |
| 2019 | 1.86 | 2.29 | 1.52 |
| 2018 | 2.22 | 2.97 | 1.64 |
| 2017 | 4.58 | 7.75 | 2.74 |
| 2016 | 9.18 | 11.46 | 7.28 |
| 2015 | 11.41 | 14.01 | 6.57 |
| 2014 | 4.13 | 7.32 | 2.51 |
| 2013 | 10.93 | 38.87 | 4.03 |
| 2012 | 11.64 | 12.84 | 9.81 |
| 2011 | 15.63 | 19.78 | 9.69 |
| 2010 | 17.9 | 23.63 | 14.56 |
| 2009 | 11.62 | 19.42 | 7.48 |
| 2008 | 11.86 | 17.05 | 7.32 |
| 2007 | 13.58 | 19.89 | 4 |
| 2006 | 3.95 | 6.57 | 2.04 |
| 2005 | 2.3 | 3.34 | 1.61 |
| 2004 | 2.76 | 4.44 | 1.94 |