| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.71 | 0.78 | 0.65 |
| 2024 | 0.73 | 0.87 | 0.58 |
| 2023 | 0.91 | 1.13 | 0.82 |
| 2022 | 1.08 | 1.45 | 0.81 |
| 2021 | 1.26 | 1.8 | 1.03 |
| 2020 | 0.96 | 1.6 | 0.84 |
| 2019 | 1.1 | 1.33 | 0.95 |
| 2018 | 1.14 | 1.32 | 0.99 |
| 2017 | 1.47 | 2.25 | 1.14 |
| 2016 | 1.59 | 2.37 | 1.42 |
| 2015 | 2.86 | 4.98 | 1.91 |
| 2014 | 1.6 | 2.61 | 1.29 |
| 2013 | 4.64 | 14.6 | 1.45 |
| 2012 | 8.12 | 13.17 | 4.66 |
| 2011 | 4.98 | 6.96 | 2.64 |
| 2010 | 2.94 | 3.71 | 2.26 |
| 2009 | 2.7 | 4.11 | 1.34 |
| 2008 | 2.47 | 5.38 | 1.11 |
| 2007 | 4.75 | 6.83 | 2.7 |
| 2006 | 2.36 | 3 | 1.68 |
| 2005 | 2.26 | 2.76 | 1.71 |
| 2004 | 3.3 | 4.12 | 2.51 |
| 2003 | 3.45 | 4.04 | 2.69 |
| 2002 | 3.97 | 4.4 | 3.7 |
| 2001 | 4.29 | 4.9 | 3.48 |
| 2000 | 7.13 | 12.73 | 4.29 |
| 1999 | 6.3 | 8.25 | 4.55 |
| 1998 | 6.9 | 8.94 | 4.79 |