| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.63 | 1.84 | 1.4 |
| 2024 | 1.34 | 1.97 | 1.12 |
| 2023 | 1.78 | 2.43 | 1.43 |
| 2022 | 1.58 | 2.05 | 1.27 |
| 2021 | 1.56 | 2.1 | 1.33 |
| 2020 | 1.6 | 2.37 | 1.3 |
| 2019 | 1.57 | 1.93 | 1.39 |
| 2018 | 2 | 2.87 | 1.4 |
| 2017 | 3.39 | 4.87 | 2.63 |
| 2016 | 3.54 | 4.77 | 2.87 |
| 2015 | 4.3 | 7.59 | 2.88 |
| 2014 | 3.04 | 7 | 2.46 |
| 2013 | 2.63 | 3.25 | 2.27 |
| 2012 | 2.57 | 2.97 | 2.33 |
| 2011 | 3.52 | 4.33 | 2.44 |
| 2010 | 4.53 | 5.54 | 3.76 |
| 2009 | 3.86 | 5.04 | 2.69 |
| 2008 | 4.33 | 6.81 | 2.28 |
| 2007 | 6.28 | 9.16 | 3.55 |
| 2006 | 3.47 | 4.82 | 2.4 |
| 2005 | 2.15 | 2.59 | 1.78 |
| 2004 | 2.57 | 3.21 | 2 |
| 2003 | 3.25 | 4.15 | 2.44 |
| 2002 | 4.21 | 5.03 | 3.16 |
| 2001 | 5.24 | 6.11 | 3.92 |
| 2000 | 5.02 | 6.44 | 2.83 |
| 1999 | 3.29 | 4.72 | 2.26 |
| 1998 | 2.59 | 3.01 | 2.19 |
| 1997 | 3.38 | 4.96 | 2.45 |