| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.81 | 2 | 1.59 |
| 2024 | 1.87 | 2.55 | 1.5 |
| 2023 | 1.94 | 2.33 | 1.52 |
| 2022 | 1.81 | 2.28 | 1.47 |
| 2021 | 1.5 | 2.21 | 1.07 |
| 2020 | 1.35 | 1.68 | 1.18 |
| 2019 | 1.56 | 2.11 | 1.22 |
| 2018 | 2.55 | 3.62 | 1.52 |
| 2017 | 4.24 | 5.32 | 3.51 |
| 2016 | 3.87 | 5.55 | 3.33 |
| 2015 | 7.84 | 12.3 | 2.6 |
| 2014 | 2.28 | 3.87 | 1.52 |
| 2013 | 1.46 | 1.63 | 1.25 |
| 2012 | 1.62 | 2.07 | 1.22 |
| 2011 | 2.78 | 3.81 | 1.6 |
| 2010 | 2.85 | 3.79 | 2.09 |
| 2009 | 2.12 | 3.47 | 1.02 |
| 2008 | 1.82 | 3.29 | 0.76 |
| 2007 | 2.51 | 4.19 | 1.16 |
| 2006 | 1.11 | 1.33 | 0.89 |
| 2005 | 1.26 | 2.06 | 0.76 |
| 2004 | 2 | 2.43 | 1.73 |
| 2003 | 2.26 | 2.8 | 1.87 |
| 2002 | 3.08 | 3.57 | 2.17 |
| 2001 | 3.61 | 4.34 | 2.73 |
| 2000 | 3.15 | 3.74 | 2.17 |
| 1999 | 2.71 | 3.43 | 2.23 |
| 1998 | 3.57 | 5.56 | 2.59 |