| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.75 | 0.78 | 0.68 |
| 2024 | 0.82 | 0.99 | 0.53 |
| 2023 | 1.14 | 1.46 | 0.92 |
| 2022 | 1.52 | 1.91 | 1.13 |
| 2021 | 1.81 | 2.73 | 1.16 |
| 2020 | 1.29 | 1.5 | 1.11 |
| 2019 | 1.39 | 1.97 | 1.18 |
| 2018 | 1.57 | 2.49 | 1.14 |
| 2017 | 2.92 | 4.16 | 2.04 |
| 2016 | 3.09 | 3.83 | 2.49 |
| 2015 | 5.43 | 10.27 | 3.06 |
| 2014 | 4.25 | 5.36 | 2.26 |
| 2013 | 2.01 | 2.88 | 1.47 |
| 2012 | 2.2 | 2.97 | 1.48 |
| 2011 | 3.3 | 4.44 | 2.15 |
| 2010 | 6.22 | 9.66 | 3.42 |
| 2009 | 5.96 | 9.25 | 2.87 |
| 2008 | 6.33 | 12.94 | 1.89 |
| 2007 | 9.65 | 16.5 | 4.24 |
| 2006 | 2.81 | 4.83 | 1.57 |
| 2005 | 1.87 | 2.95 | 1.15 |
| 2004 | 6.7 | 12.93 | 2.64 |
| 2003 | 9.09 | 10.63 | 6.84 |
| 2002 | 8.56 | 9.98 | 6.34 |
| 2001 | 7.1 | 8.41 | 5.76 |
| 2000 | 6.55 | 8.07 | 4.93 |