| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.37 | 1.49 | 1.23 |
| 2024 | 1.28 | 1.59 | 1 |
| 2023 | 1.67 | 2.01 | 1.32 |
| 2022 | 1.53 | 1.79 | 1.3 |
| 2021 | 1.73 | 2.19 | 1.48 |
| 2020 | 1.97 | 2.45 | 1.68 |
| 2019 | 2.37 | 3.3 | 1.96 |
| 2018 | 2.44 | 3.48 | 1.7 |
| 2017 | 3.29 | 5.16 | 2.42 |
| 2016 | 3.37 | 3.96 | 2.74 |
| 2015 | 4.19 | 6.7 | 2.41 |
| 2014 | 3.3 | 4.24 | 2.31 |
| 2013 | 2.41 | 3.27 | 1.93 |
| 2012 | 2.23 | 3.13 | 1.69 |
| 2011 | 3.14 | 3.95 | 2.15 |
| 2010 | 3.48 | 4.37 | 2.44 |
| 2009 | 4.03 | 6.46 | 2.39 |
| 2008 | 4.3 | 8.49 | 1.93 |
| 2007 | 3.86 | 5.86 | 1.84 |
| 2006 | 2.02 | 2.44 | 1.62 |
| 2005 | 2.26 | 2.95 | 1.68 |
| 2004 | 3.61 | 5.66 | 2.53 |
| 2003 | 5.47 | 6.56 | 3.74 |
| 2002 | 7.32 | 8.25 | 5.8 |
| 2001 | 9.08 | 10.57 | 7.12 |
| 2000 | 9.79 | 12.09 | 8.03 |
| 1999 | 6.49 | 9.75 | 3.76 |
| 1998 | 4.45 | 5.42 | 3.16 |
| 1997 | 3.89 | 5.31 | 2.84 |