| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 8.98 | 9.86 | 7.91 |
| 2024 | 5.93 | 13.54 | 3.6 |
| 2023 | 5.78 | 6.63 | 5.05 |
| 2022 | 6.74 | 9.01 | 5.76 |
| 2021 | 7.57 | 9.63 | 6.78 |
| 2020 | 9.07 | 10.76 | 7.74 |
| 2019 | 9.77 | 11.66 | 7.92 |
| 2018 | 10 | 14.14 | 7.65 |
| 2017 | 22.97 | 34.74 | 13.4 |
| 2016 | 36.02 | 56.87 | 27.91 |
| 2015 | 17.92 | 91.96 | 10.54 |
| 2014 | 0 | -0.33 | |
| 2013 | 0 | -1.42 | |
| 2012 | 3.6 | 4 | 3.06 |
| 2011 | 3.9 | 4.76 | 3.08 |
| 2010 | 3.43 | 4.27 | 2.7 |
| 2009 | 2.57 | 3.27 | 1.88 |
| 2008 | 3.67 | 7.74 | 1.48 |
| 2007 | 5.24 | 8.15 | 1.73 |
| 2006 | 1.65 | 2.36 | 1.18 |
| 2005 | 1.51 | 2.18 | 1.03 |
| 2004 | 2.57 | 3.3 | 1.65 |
| 2003 | 2.18 | 2.5 | 1.81 |
| 2002 | 2.24 | 2.72 | 1.48 |
| 2001 | 2.7 | 3.32 | 1.93 |
| 2000 | 2.86 | 3.22 | 2.47 |
| 1999 | 2.46 | 3.94 | 1.81 |
| 1998 | 3.34 | 5.59 | 1.83 |
| 1997 | 4.8 | 6.7 | 3.08 |