| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.62 | 0.66 | 0.56 |
| 2024 | 0.6 | 0.88 | 0.48 |
| 2023 | 0.69 | 0.8 | 0.62 |
| 2022 | 0.77 | 0.92 | 0.66 |
| 2021 | 0.95 | 1.07 | 0.82 |
| 2020 | 1.24 | 1.51 | 1.05 |
| 2019 | 1.62 | 2.3 | 1.32 |
| 2018 | 1.96 | 3.03 | 1.39 |
| 2017 | 3.08 | 3.64 | 2.23 |
| 2016 | 2.65 | 3.38 | 2.12 |
| 2015 | 4.27 | 6.04 | 2.47 |
| 2014 | 2.48 | 3.6 | 2.06 |
| 2013 | 2.37 | 3.77 | 1.59 |
| 2012 | 4.11 | 7.36 | 1.75 |
| 2011 | 5.91 | 7.25 | 3.87 |
| 2010 | 7.02 | 8.62 | 5.15 |
| 2009 | 8.05 | 11.12 | 4.5 |
| 2008 | 7.02 | 12.11 | 3.41 |
| 2007 | 11.25 | 15.79 | 6.17 |
| 2006 | 4.56 | 6.98 | 1.83 |
| 2005 | 1.69 | 2.27 | 1.16 |
| 2004 | 2.06 | 2.78 | 1.65 |
| 2003 | 2.69 | 3.4 | 2.13 |
| 2002 | 2.43 | 2.91 | 1.57 |
| 2001 | 2.79 | 3.33 | 2.26 |
| 2000 | 2.61 | 3.17 | 2.13 |
| 1999 | 2.77 | 4.82 | 2.08 |
| 1998 | 4.35 | 5.72 | 3.09 |
| 1997 | 6.44 | 11.04 | 4.29 |