| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.94 | 1.02 | 0.84 |
| 2024 | 0.96 | 1.56 | 0.62 |
| 2023 | 1.4 | 2.03 | 1.19 |
| 2022 | 1.2 | 1.48 | 0.78 |
| 2021 | 0.91 | 1.18 | 0.71 |
| 2020 | 1.13 | 1.28 | 1.01 |
| 2019 | 1.32 | 1.7 | 1.11 |
| 2018 | 1.32 | 1.71 | 0.95 |
| 2017 | 2.11 | 3.82 | 1.56 |
| 2016 | 3.45 | 4.53 | 2.48 |
| 2015 | 4.78 | 7.76 | 2.79 |
| 2014 | 2.71 | 4.87 | 2.08 |
| 2013 | 2.99 | 3.96 | 2.36 |
| 2012 | 3.42 | 4.83 | 2.57 |
| 2011 | 5.05 | 6.55 | 3.16 |
| 2010 | 4.55 | 6.38 | 3.07 |
| 2009 | 3.61 | 5.16 | 1.86 |
| 2008 | 3.48 | 7.42 | 1.47 |
| 2007 | 5.64 | 9.12 | 1.38 |
| 2006 | 1.29 | 1.46 | 1.04 |
| 2005 | 1.5 | 2.07 | 1.18 |
| 2004 | 2.6 | 4.04 | 1.31 |
| 2003 | 3.07 | 3.62 | 2.4 |
| 2002 | 4.86 | 5.9 | 4.33 |
| 2001 | 6.36 | 7.58 | 4.73 |