| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.61 | 1.91 | 1.15 |
| 2024 | 1.64 | 2.29 | 1.22 |
| 2023 | 1.85 | 3.08 | 1.5 |
| 2022 | 1.36 | 1.96 | 0.89 |
| 2021 | 1.64 | 2.18 | 1.42 |
| 2020 | 2.04 | 2.63 | 1.53 |
| 2019 | 1.72 | 2.43 | 1.33 |
| 2018 | 2.24 | 2.82 | 1.56 |
| 2017 | 2.43 | 2.78 | 2.13 |
| 2016 | 2.16 | 2.38 | 1.64 |
| 2015 | 3.81 | 6.3 | 2.23 |
| 2014 | 3 | 3.77 | 2.23 |
| 2013 | 2.86 | 3.95 | 2.25 |
| 2012 | 4.34 | 7.35 | 2.4 |
| 2011 | 9.16 | 15.96 | 4.77 |
| 2010 | 4.45 | 6.95 | 3.07 |
| 2009 | 3.7 | 5.34 | 1.73 |
| 2008 | 3.55 | 6.4 | 1.5 |
| 2007 | 4.85 | 6.85 | 3.59 |
| 2006 | 3.66 | 4.43 | 2.99 |
| 2005 | 3.47 | 4.27 | 2.95 |
| 2004 | 3.91 | 7.05 | 2.43 |
| 2003 | 4.57 | 6.28 | 3.22 |
| 2002 | 6.02 | 8.58 | 4.39 |
| 2001 | 9.04 | 10.7 | 7.93 |
| 2000 | 7.94 | 9.27 | 6.5 |
| 1999 | 6.26 | 8.64 | 4.44 |
| 1998 | 5.8 | 7.89 | 3.4 |
| 1997 | 3.78 | 6.02 | 2.89 |