| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.13 | 1.31 | 0.97 |
| 2024 | 1 | 1.51 | 0.69 |
| 2023 | 1.34 | 1.73 | 1.08 |
| 2022 | 2.32 | 4.32 | 1.4 |
| 2021 | 3.54 | 4.8 | 2.63 |
| 2020 | 1.57 | 2.86 | 1.11 |
| 2019 | 1.65 | 2.41 | 1.29 |
| 2018 | 1.91 | 2.79 | 1.32 |
| 2017 | 3.83 | 5.44 | 2.42 |
| 2016 | 10.75 | 18.04 | 5.19 |
| 2015 | 13.75 | 32.19 | 4.78 |
| 2014 | 4.08 | 5.93 | 3.36 |
| 2013 | 3.52 | 4.06 | 2.79 |
| 2012 | 4.38 | 6.45 | 3.06 |
| 2011 | 5.75 | 7.91 | 3.69 |
| 2010 | 5.92 | 7.11 | 4.51 |
| 2009 | 5.04 | 6.65 | 3.15 |
| 2008 | 5.59 | 10.15 | 2.31 |
| 2007 | 7.12 | 12.19 | 2.93 |
| 2006 | 3.95 | 5.41 | 2.96 |
| 2005 | 7.14 | 9.3 | 3.9 |
| 2004 | 11.68 | 27.08 | 7.17 |
| 2003 | 24.26 | 27.89 | 21.08 |
| 2002 | 19.2 | 24.28 | 11.7 |
| 2001 | 17 | 20.45 | 12.78 |
| 2000 | 20.81 | 29.17 | 13.82 |
| 1999 | 10.76 | 16.97 | 6.12 |
| 1998 | 6.61 | 10.82 | 4.33 |
| 1997 | 5.74 | 7.41 | 4.36 |