| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.45 | 1.73 | 1.35 |
| 2024 | 1.33 | 1.7 | 1.07 |
| 2023 | 1.75 | 2.29 | 1.49 |
| 2022 | 1.87 | 2.97 | 1.57 |
| 2021 | 1.67 | 2.04 | 1.5 |
| 2020 | 1.92 | 2.5 | 1.69 |
| 2019 | 1.92 | 2.57 | 1.26 |
| 2018 | 2.27 | 3.26 | 1.68 |
| 2017 | 2.34 | 2.9 | 1.9 |
| 2016 | 1.98 | 2.46 | 1.56 |
| 2015 | 1.97 | 3.06 | 1.2 |
| 2014 | 2.3 | 4.06 | 1.35 |
| 2013 | 1.38 | 1.7 | 1.13 |
| 2012 | 1.39 | 1.82 | 1.03 |
| 2011 | 2.39 | 3.8 | 1.27 |
| 2010 | 3.15 | 4.62 | 2.22 |
| 2009 | 4.64 | 6.34 | 3.73 |
| 2008 | 4.71 | 7.26 | 2.15 |
| 2007 | 3.67 | 6.57 | 1.19 |
| 2006 | 1.12 | 1.44 | 0.79 |
| 2005 | 1.15 | 1.63 | 0.8 |
| 2004 | 2.07 | 2.93 | 1.42 |
| 2003 | 2.92 | 4.11 | 2.25 |
| 2002 | 2.89 | 3.44 | 2.14 |
| 2001 | 3.22 | 3.75 | 2.35 |
| 2000 | 2.78 | 3.45 | 2.05 |
| 1999 | 1.91 | 2.4 | 1.55 |
| 1998 | 1.77 | 2.08 | 1.4 |
| 1997 | 1.74 | 2.71 | 1.2 |