| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.99 | 1.09 | 0.94 |
| 2024 | 1.01 | 1.18 | 0.86 |
| 2023 | 1.11 | 1.48 | 0.93 |
| 2022 | 1.15 | 1.41 | 0.96 |
| 2021 | 1.41 | 2.53 | 1.16 |
| 2020 | 2.09 | 2.78 | 1.45 |
| 2019 | 1.88 | 2.32 | 1.5 |
| 2018 | 2.97 | 4.84 | 1.55 |
| 2017 | 4.46 | 7.89 | 3.54 |
| 2016 | 3.27 | 4.91 | 2.43 |
| 2015 | 3.11 | 4.61 | 1.96 |
| 2014 | 1.65 | 2.53 | 1.36 |
| 2013 | 1.84 | 2.54 | 1.4 |
| 2012 | 2.15 | 2.67 | 1.81 |
| 2011 | 2.82 | 3.96 | 1.72 |
| 2010 | 2.85 | 3.6 | 2.25 |
| 2009 | 6.92 | 12.37 | 2.55 |
| 2008 | 8.33 | 14.87 | 2.97 |
| 2007 | 19.68 | 56.45 | 9.86 |
| 2006 | 13.55 | 22.65 | 5.75 |
| 2005 | 4.11 | 6.83 | 2.46 |
| 2004 | 5.63 | 13.6 | 2.21 |
| 2003 | 6.78 | 6.78 | 6.78 |
| 2002 | 5.68 | 6.72 | 4.74 |
| 2001 | 4.83 | 5.84 | 3.05 |
| 2000 | 4.55 | 6.14 | 3.05 |