| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.72 | 2 | 1.51 |
| 2024 | 1.66 | 2.3 | 1.29 |
| 2023 | 2.23 | 2.43 | 1.99 |
| 2022 | 2.51 | 3.44 | 2.07 |
| 2021 | 2.8 | 3.22 | 2.33 |
| 2020 | 3.27 | 4.29 | 2.63 |
| 2019 | 2.47 | 2.92 | 2.11 |
| 2018 | 2.63 | 3.48 | 1.81 |
| 2017 | 4.34 | 5.96 | 3.24 |
| 2016 | 5.33 | 6.55 | 3.87 |
| 2015 | 5.04 | 9.78 | 2.91 |
| 2014 | 2.59 | 3.84 | 1.72 |
| 2013 | 2.07 | 2.45 | 1.68 |
| 2012 | 2.58 | 3.4 | 1.68 |
| 2011 | 4.36 | 6.08 | 2.78 |
| 2010 | 4.92 | 6.04 | 3.57 |
| 2009 | 3.78 | 5.28 | 2.01 |
| 2008 | 7.73 | 23.02 | 1.44 |
| 2007 | 10.19 | 16.63 | 4.81 |
| 2006 | 4.7 | 6.08 | 3.1 |
| 2005 | 3.26 | 4.63 | 2.33 |
| 2004 | 4.22 | 5.54 | 3.2 |
| 2003 | 5.23 | 5.96 | 3.9 |
| 2002 | 7.93 | 12.29 | 3.8 |
| 2001 | 12.7 | 14.87 | 10.07 |
| 2000 | 12.83 | 15.33 | 9.31 |
| 1999 | 10.55 | 17.52 | 5.97 |
| 1998 | 7.67 | 10.91 | 4.83 |
| 1997 | 5.13 | 8.13 | 3.74 |