| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.68 | 0.73 | 0.63 |
| 2024 | 0.59 | 0.93 | 0.43 |
| 2023 | 0.74 | 0.85 | 0.64 |
| 2022 | 0.78 | 0.94 | 0.67 |
| 2021 | 1 | 1.23 | 0.88 |
| 2020 | 1.02 | 1.23 | 0.93 |
| 2019 | 1.18 | 1.55 | 1 |
| 2018 | 1.69 | 2.49 | 1.15 |
| 2017 | 2.1 | 2.81 | 1.75 |
| 2016 | 1.96 | 2.37 | 1.7 |
| 2015 | 2.54 | 4.86 | 1.63 |
| 2014 | 1.48 | 1.89 | 1.22 |
| 2013 | 1.6 | 2.63 | 1.1 |
| 2012 | 1.07 | 1.62 | 0.8 |
| 2011 | 1.49 | 2.19 | 0.82 |
| 2010 | 1.89 | 2.98 | 1.31 |
| 2009 | 1.46 | 2.17 | 0.94 |
| 2008 | 1.58 | 2.97 | 0.78 |
| 2007 | 2.28 | 3.44 | 1.2 |
| 2006 | 1.2 | 1.61 | 0.97 |
| 2005 | 1.16 | 2.4 | 0.86 |
| 2004 | 2.36 | 3.33 | 1.66 |
| 2003 | 3.52 | 4.41 | 2.5 |
| 2002 | 7 | 14.37 | 3.68 |