| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.28 | 1.63 | 1.04 |
| 2023 | 1.31 | 1.69 | 1.04 |
| 2022 | 1.57 | 2.06 | 1.15 |
| 2021 | 2.56 | 3.19 | 1.95 |
| 2020 | 2.03 | 2.57 | 1.68 |
| 2019 | 2.15 | 2.82 | 1.51 |
| 2018 | 1.77 | 2.44 | 1.41 |
| 2017 | 1.73 | 2.49 | 1.4 |
| 2016 | 1.59 | 1.88 | 1.48 |
| 2015 | 2.4 | 3.31 | 1.63 |
| 2014 | 2.09 | 2.75 | 1.74 |
| 2013 | 2.43 | 3.31 | 1.85 |
| 2012 | 2.45 | 3.59 | 1.71 |
| 2011 | 3.48 | 4.66 | 2.9 |
| 2010 | 4.24 | 5.43 | 3.32 |
| 2009 | 4.49 | 5.97 | 2.26 |
| 2008 | 4.91 | 10.93 | 1.99 |
| 2007 | 7.84 | 10.84 | 4.36 |
| 2006 | 3.22 | 4.84 | 2.63 |
| 2005 | 2.72 | 3.25 | 2.38 |
| 2004 | 5.16 | 7.79 | 3.08 |
| 2003 | 6.33 | 8.43 | 4.7 |
| 2002 | 9.57 | 13.78 | 4.92 |
| 2001 | 19.34 | 26.63 | 13.67 |
| 2000 | 21.68 | 23.97 | 19.07 |
| 1999 | 23.26 | 29.53 | 12.24 |
| 1998 | 24.02 | 25.62 | 22.09 |
| 1997 | 23.01 | 29.16 | 14.9 |