| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 3.3 | 4.26 | 2.29 |
| 2023 | 2.8 | 3.37 | 2.05 |
| 2022 | 2.32 | 2.97 | 1.86 |
| 2021 | 2.74 | 3.99 | 2.15 |
| 2020 | 2.4 | 3.64 | 1.62 |
| 2019 | 1.94 | 2.41 | 1.47 |
| 2018 | 2.63 | 4.32 | 1.4 |
| 2017 | 4.26 | 6.42 | 2.7 |
| 2016 | 3.89 | 6.14 | 2.63 |
| 2015 | 2.75 | 4.36 | 2.1 |
| 2014 | 2.19 | 2.67 | 1.43 |
| 2013 | 2.53 | 3.54 | 2 |
| 2012 | 3.76 | 5.67 | 2.5 |
| 2011 | 5.9 | 8.4 | 3.34 |
| 2010 | 4.28 | 6.69 | 2.65 |
| 2009 | 2.76 | 4.95 | 0.94 |
| 2008 | 2.13 | 3.57 | 0.86 |
| 2007 | 2.22 | 3.27 | 0.93 |
| 2006 | 0.9 | 1.07 | 0.75 |
| 2005 | 0.87 | 1.1 | 0.72 |
| 2004 | 1.43 | 3.38 | 0.99 |
| 2003 | 1.78 | 2.14 | 1.51 |
| 2002 | 2.5 | 3.12 | 2.1 |
| 2001 | 3.62 | 4.28 | 2.67 |
| 2000 | 3.47 | 4.34 | 2.34 |
| 1999 | 2.71 | 3.76 | 1.92 |
| 1998 | 4.72 | 8.59 | 2.03 |
| 1997 | 6.32 | 8.09 | 4.84 |