| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.03 | 4.42 | 1.68 |
| 2024 | 1.65 | 2.2 | 1.23 |
| 2023 | 2.01 | 2.23 | 1.73 |
| 2022 | 2.1 | 2.91 | 1.59 |
| 2021 | 1.98 | 2.65 | 1.46 |
| 2020 | 1.88 | 2.33 | 1.67 |
| 2019 | 2.14 | 3.17 | 1.7 |
| 2018 | 2.27 | 3.22 | 1.59 |
| 2017 | 4.57 | 7.11 | 2.97 |
| 2016 | 5.9 | 7.67 | 4.7 |
| 2015 | 6.94 | 15.07 | 3.73 |
| 2014 | 2.89 | 4.62 | 2.03 |
| 2013 | 2.43 | 3.47 | 1.87 |
| 2012 | 2.52 | 3.3 | 1.46 |
| 2011 | 3.06 | 4.08 | 1.54 |
| 2010 | 4.43 | 7.81 | 3.05 |
| 2009 | 5.73 | 7.2 | 3.16 |
| 2008 | 10.52 | 23.31 | 2.39 |
| 2007 | 6.41 | 13.92 | 1.97 |
| 2006 | 2.03 | 2.57 | 1.39 |
| 2005 | 1.31 | 1.67 | 0.89 |
| 2004 | 2.48 | 3.84 | 1.53 |
| 2003 | 4.15 | 4.84 | 3.07 |
| 2002 | 4.49 | 5.42 | 2.76 |
| 2001 | 6.31 | 8.23 | 4.1 |
| 2000 | 6.62 | 10.38 | 4.6 |
| 1999 | 5.12 | 7.7 | 3.93 |
| 1998 | 4.65 | 6.94 | 3.28 |
| 1997 | 4.43 | 6.23 | 3.25 |