| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.69 | 0.71 | 0.67 |
| 2024 | 0.68 | 0.79 | 0.57 |
| 2023 | 0.76 | 0.94 | 0.62 |
| 2022 | 1.01 | 1.35 | 0.71 |
| 2021 | 1.52 | 2 | 1.11 |
| 2020 | 2.11 | 2.5 | 1.76 |
| 2019 | 1.81 | 2.28 | 1.44 |
| 2018 | 1.93 | 2.35 | 1.49 |
| 2017 | 1.56 | 2.01 | 1.24 |
| 2016 | 1.2 | 1.35 | 1 |
| 2015 | 1.62 | 2.17 | 1.21 |
| 2014 | 1.55 | 1.87 | 1.38 |
| 2013 | 1.8 | 2.46 | 1.36 |
| 2012 | 1.9 | 2.31 | 1.51 |
| 2011 | 3.17 | 4.5 | 1.86 |
| 2010 | 2.59 | 3.44 | 1.89 |
| 2009 | 2.84 | 3.64 | 2.06 |
| 2008 | 5.85 | 12.73 | 1.11 |
| 2007 | 9.69 | 15.29 | 5.33 |
| 2006 | 3.1 | 5.84 | 2.02 |
| 2005 | 1.24 | 2.25 | 0.91 |
| 2004 | 2.45 | 5.15 | 1.23 |
| 2003 | 2.88 | 3.87 | 2.41 |