| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.82 | 2.01 | 1.64 |
| 2024 | 1.64 | 2.41 | 1.25 |
| 2023 | 1.95 | 2.36 | 1.66 |
| 2022 | 1.5 | 2.29 | 1.12 |
| 2021 | 1.53 | 1.89 | 1.22 |
| 2020 | 1.48 | 2.06 | 1.22 |
| 2019 | 1.46 | 1.87 | 1.13 |
| 2018 | 1.57 | 2.19 | 1.1 |
| 2017 | 2.69 | 4.04 | 2.07 |
| 2016 | 2.98 | 3.62 | 2.1 |
| 2015 | 2.99 | 5.38 | 1.9 |
| 2014 | 2.08 | 2.68 | 1.54 |
| 2013 | 1.95 | 3.12 | 1.48 |
| 2012 | 1.89 | 2.55 | 1.39 |
| 2011 | 2.79 | 4.03 | 1.87 |
| 2010 | 6.54 | 10.25 | 3.28 |
| 2009 | 4.99 | 8.03 | 2.93 |
| 2008 | 4.1 | 7.38 | 2.17 |
| 2007 | 5.1 | 7.67 | 3.16 |
| 2006 | 4.39 | 6.27 | 2.97 |
| 2005 | 3.3 | 4.27 | 2.4 |
| 2004 | 5.05 | 8.53 | 3.74 |
| 2003 | 4.72 | 6.54 | 3.39 |
| 2002 | 7.37 | 9.29 | 5.79 |
| 2001 | 9.53 | 11.47 | 7.98 |
| 2000 | 8.05 | 10.17 | 5.91 |
| 1999 | 6.53 | 8.57 | 4.24 |
| 1998 | 2.9 | 3.73 | 2.25 |
| 1997 | 2.55 | 3.88 | 1.79 |