| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.14 | 2.3 | 1.81 |
| 2024 | 1.66 | 2.52 | 1.25 |
| 2023 | 2.03 | 2.83 | 1.73 |
| 2022 | 1.81 | 2.31 | 1.5 |
| 2021 | 1.51 | 2.09 | 1.2 |
| 2020 | 1.51 | 1.84 | 1.24 |
| 2019 | 1.64 | 2.32 | 1.25 |
| 2018 | 1.55 | 2.01 | 1.08 |
| 2017 | 2.67 | 3.67 | 1.87 |
| 2016 | 5.31 | 6.94 | 3.54 |
| 2015 | 5.18 | 9.12 | 2.3 |
| 2014 | 2.78 | 3.73 | 2.07 |
| 2013 | 3.1 | 4.25 | 2.2 |
| 2012 | 2.45 | 2.91 | 1.99 |
| 2011 | 3.55 | 5.11 | 2.29 |
| 2010 | 3.19 | 4 | 2.37 |
| 2009 | 2.59 | 3.33 | 1.39 |
| 2008 | 3 | 5.9 | 1.09 |
| 2007 | 4.41 | 7.31 | 1.94 |
| 2006 | 2.08 | 2.75 | 1.73 |
| 2005 | 2.35 | 3.32 | 1.7 |
| 2004 | 3.5 | 4.78 | 2.29 |
| 2003 | 4.56 | 6.07 | 3.07 |
| 2002 | 6.81 | 11.34 | 4.49 |
| 2001 | 10.34 | 12.34 | 8.34 |
| 2000 | 12.97 | 15.8 | 10.75 |
| 1999 | 10.3 | 17.62 | 6.52 |
| 1998 | 8.02 | 10.37 | 6.43 |
| 1997 | 6.91 | 8.98 | 4.47 |