| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.36 | 2.61 | 2.09 |
| 2024 | 1.97 | 3.02 | 1.27 |
| 2023 | 2.55 | 3.26 | 1.93 |
| 2022 | 3.17 | 4.4 | 2.14 |
| 2021 | 2.96 | 4.85 | 1.36 |
| 2020 | 1.88 | 2.33 | 1.53 |
| 2019 | 2.23 | 2.7 | 2.02 |
| 2018 | 2.05 | 2.41 | 1.68 |
| 2017 | 2.8 | 3.36 | 2.22 |
| 2016 | 4.33 | 5.75 | 3.03 |
| 2015 | 6.34 | 9.14 | 2.86 |
| 2014 | 2.97 | 3.65 | 2.16 |
| 2013 | 2.73 | 3.39 | 1.98 |
| 2012 | 3.64 | 6.35 | 2.39 |
| 2011 | 7.51 | 11.51 | 4.29 |
| 2010 | 28.49 | 84.63 | 5.68 |
| 2009 | 23.55 | 36.51 | 6.84 |
| 2008 | 8.99 | 15.92 | 4.16 |
| 2007 | 12.7 | 19.53 | 4.29 |
| 2006 | 4 | 5.17 | 3.18 |
| 2005 | 4.1 | 5.55 | 3.01 |
| 2004 | 5.12 | 7.94 | 2.34 |
| 2003 | 8.37 | 10.24 | 5.75 |
| 2002 | 6.73 | 7.72 | 4.85 |
| 2001 | 8.24 | 10.4 | 6.45 |
| 2000 | 7.78 | 9.63 | 5.03 |
| 1999 | 4.69 | 6 | 3.6 |
| 1998 | 4.27 | 5.34 | 3.38 |
| 1997 | 4.08 | 6.24 | 3.26 |