| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.69 | 1.92 | 1.45 |
| 2024 | 1.41 | 1.69 | 1.13 |
| 2023 | 1.37 | 1.68 | 1.05 |
| 2022 | 1.2 | 1.63 | 1.01 |
| 2021 | 1.47 | 1.99 | 1.24 |
| 2020 | 1.33 | 1.63 | 1.1 |
| 2019 | 1.14 | 1.45 | 0.91 |
| 2018 | 1.18 | 1.44 | 0.91 |
| 2017 | 1.25 | 1.46 | 1.07 |
| 2016 | 1.13 | 1.33 | 0.95 |
| 2015 | 1.54 | 2.02 | 1.14 |
| 2014 | 0.86 | 1.61 | 0.69 |
| 2013 | 1.1 | 1.67 | 0.82 |
| 2012 | 1.74 | 2.33 | 1.2 |
| 2011 | 3.68 | 5.69 | 1.82 |
| 2010 | 6.27 | 8.86 | 4.29 |
| 2009 | 12.73 | 25.4 | 6.94 |
| 2008 | 7.97 | 13.26 | 4.66 |
| 2007 | 8.04 | 12.51 | 3.22 |
| 2006 | 2.69 | 3.64 | 1.58 |
| 2005 | 1.6 | 2.26 | 0.85 |
| 2004 | 2.99 | 4.2 | 2.16 |
| 2003 | 4.56 | 9.03 | 2.53 |
| 2002 | 10.71 | 14.73 | 9 |
| 2001 | 12.43 | 14.73 | 9.63 |
| 2000 | 9.47 | 13.36 | 4.8 |
| 1999 | 4.02 | 5.95 | 2.77 |
| 1998 | 3.63 | 4.32 | 3.02 |
| 1997 | 3.73 | 5.18 | 2.53 |