| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.85 | 1.92 | 1.79 |
| 2024 | 1.79 | 2.12 | 1.44 |
| 2023 | 1.66 | 1.93 | 1.38 |
| 2022 | 1.59 | 1.97 | 1.33 |
| 2021 | 2.22 | 2.83 | 1.9 |
| 2020 | 2.29 | 2.76 | 1.98 |
| 2019 | 2.36 | 3.23 | 1.84 |
| 2018 | 2.1 | 2.45 | 1.79 |
| 2017 | 3.05 | 4.17 | 2.34 |
| 2016 | 3.95 | 4.61 | 3.27 |
| 2015 | 5.43 | 10.36 | 2.77 |
| 2014 | 2 | 3.06 | 1.55 |
| 2013 | 3.24 | 6.38 | 1.88 |
| 2012 | 2.33 | 3.06 | 1.87 |
| 2011 | 3.64 | 5.08 | 1.99 |
| 2010 | 4.53 | 5.91 | 2.9 |
| 2009 | 4.58 | 5.94 | 3.38 |
| 2008 | 11.21 | 21.41 | 2.44 |
| 2007 | 10.12 | 14.62 | 7.69 |
| 2006 | 5.8 | 7.88 | 4.37 |
| 2005 | 4.47 | 5.96 | 3.27 |
| 2004 | 5.8 | 12.06 | 2.09 |
| 2003 | 25.55 | 32.82 | 10.86 |
| 2002 | 28.25 | 39.12 | 10.29 |
| 2001 | 10.4 | 11.55 | 9.57 |
| 2000 | 9.32 | 12.79 | 5.16 |
| 1999 | 6.36 | 7.81 | 5.56 |
| 1998 | 6.9 | 9.11 | 4.39 |
| 1997 | 6.29 | 8.04 | 4.28 |