| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.81 | 2.03 | 1.62 |
| 2024 | 2.12 | 2.4 | 1.81 |
| 2023 | 1.85 | 2.04 | 1.66 |
| 2022 | 1.67 | 1.99 | 1.47 |
| 2021 | 1.77 | 2.17 | 1.59 |
| 2020 | 1.55 | 1.72 | 1.38 |
| 2019 | 1.65 | 1.82 | 1.47 |
| 2018 | 1.69 | 2.11 | 1.45 |
| 2017 | 2.01 | 2.14 | 1.92 |
| 2016 | 2.04 | 2.61 | 1.87 |
| 2015 | 3.21 | 4.41 | 2.49 |
| 2014 | 2.5 | 3.56 | 2.12 |
| 2013 | 2.32 | 2.74 | 1.93 |
| 2012 | 1.75 | 2.3 | 1.49 |
| 2011 | 2.22 | 2.98 | 1.63 |
| 2010 | 3.83 | 8.25 | 2.1 |
| 2009 | 6.24 | 7.94 | 5 |
| 2008 | 9.56 | 22.54 | 2.99 |
| 2007 | 6.29 | 17.95 | 1.91 |
| 2006 | 2.14 | 3.11 | 1.69 |
| 2005 | 1.8 | 2.55 | 1.23 |
| 2004 | 3.39 | 4.59 | 2.47 |
| 2003 | 3.78 | 4.85 | 2.67 |
| 2002 | 6.81 | 8.53 | 5.44 |
| 2001 | 8.31 | 10.84 | 5.13 |
| 2000 | 6.89 | 11.35 | 3.71 |
| 1999 | 3.98 | 5.39 | 2.99 |
| 1998 | 4.12 | 5.81 | 2.62 |
| 1997 | 2.99 | 4.32 | 1.98 |