| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.65 | 1.9 | 1.49 |
| 2024 | 1.54 | 2.11 | 1.05 |
| 2023 | 1.86 | 2.06 | 1.67 |
| 2022 | 1.83 | 2.13 | 1.59 |
| 2021 | 1.86 | 2.12 | 1.62 |
| 2020 | 2.55 | 3.52 | 1.95 |
| 2019 | 2.8 | 3.62 | 2.34 |
| 2018 | 3.89 | 5.17 | 2.79 |
| 2017 | 6.19 | 8.46 | 4.6 |
| 2016 | 8.88 | 11.57 | 6.99 |
| 2015 | 7.5 | 13.86 | 3.85 |
| 2014 | 3.4 | 5.47 | 2.28 |
| 2013 | 2.37 | 2.76 | 1.9 |
| 2012 | 2.15 | 2.75 | 1.69 |
| 2011 | 3.3 | 4.31 | 2.04 |
| 2010 | 4.01 | 5.34 | 2.77 |
| 2009 | 4.1 | 5.78 | 2.71 |
| 2008 | 5.58 | 13.65 | 1.84 |
| 2007 | 11.05 | 24.08 | 1.82 |
| 2006 | 1.57 | 2.33 | 1.05 |
| 2005 | 1.13 | 1.39 | 0.87 |
| 2004 | 1.76 | 2.34 | 1.33 |
| 2003 | 2.37 | 3.2 | 1.67 |
| 2002 | 4.01 | 4.61 | 3.38 |
| 2001 | 5.28 | 6.62 | 3.77 |
| 2000 | 5.94 | 6.98 | 4.44 |