| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.11 | 1.24 | 1 |
| 2024 | 1.43 | 1.91 | 1 |
| 2023 | 1.68 | 2.47 | 1.28 |
| 2022 | 1.99 | 2.8 | 1.44 |
| 2021 | 1.49 | 3.13 | 0.84 |
| 2020 | 0.83 | 1.09 | 0.7 |
| 2019 | 0.93 | 1.19 | 0.82 |
| 2018 | 1.27 | 1.97 | 0.87 |
| 2017 | 1.72 | 2.17 | 1.34 |
| 2016 | 1.65 | 2.17 | 1.08 |
| 2015 | 1.44 | 2.28 | 0.98 |
| 2014 | 1.14 | 1.68 | 0.94 |
| 2013 | 1.9 | 2.88 | 1.3 |
| 2012 | 3.09 | 3.9 | 2.05 |
| 2011 | 5.21 | 7.09 | 3.1 |
| 2010 | 6.77 | 9.79 | 4.74 |
| 2009 | 7.2 | 10.29 | 3.7 |
| 2008 | 7.5 | 15.29 | 2.22 |
| 2007 | 8.1 | 17.26 | 2.3 |
| 2006 | 1.86 | 2.31 | 1.45 |
| 2005 | 2.34 | 3.53 | 1.2 |
| 2004 | 2.95 | 3.71 | 2.4 |
| 2003 | 2.05 | 2.74 | 1.74 |
| 2002 | 2.31 | 2.62 | 2.08 |
| 2001 | 3.18 | 4.13 | 2.12 |