| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.95 | 1.11 | 0.82 |
| 2024 | 0.86 | 1.38 | 0.62 |
| 2023 | 1.02 | 1.41 | 0.84 |
| 2022 | 1.1 | 1.8 | 0.82 |
| 2021 | 0.86 | 1.3 | 0.75 |
| 2020 | 1.07 | 1.35 | 0.96 |
| 2019 | 1.26 | 2.11 | 1.01 |
| 2018 | 1.45 | 2.04 | 0.97 |
| 2017 | 2.5 | 4.42 | 1.71 |
| 2016 | 2.48 | 3.52 | 1.94 |
| 2015 | 2.71 | 4.88 | 1.84 |
| 2014 | 1.6 | 2.17 | 1.27 |
| 2013 | 1.3 | 1.67 | 1.02 |
| 2012 | 1.46 | 1.8 | 1.18 |
| 2011 | 2.21 | 2.84 | 1.36 |
| 2010 | 3.52 | 4.88 | 2.66 |
| 2009 | 3.96 | 6.14 | 1.8 |
| 2008 | 2.67 | 4.73 | 1.32 |
| 2007 | 6.3 | 17.17 | 2.39 |
| 2006 | 2.87 | 3.66 | 2 |
| 2005 | 3.16 | 4.7 | 1.91 |
| 2004 | 5.53 | 8.33 | 3.9 |
| 2003 | 9.75 | 17.15 | 6.37 |
| 2002 | 34.15 | 62.96 | 4.11 |
| 2001 | 10.25 | 12.33 | 7.02 |
| 2000 | 10.13 | 12.15 | 8.76 |
| 1999 | 13.27 | 29.71 | 4.17 |
| 1998 | 6.13 | 7.89 | 4.64 |
| 1997 | 6.67 | 9.57 | 4.55 |