| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.99 | 2.91 | 1.6 |
| 2024 | 1.56 | 2.01 | 1.13 |
| 2023 | 1.83 | 2.41 | 1.43 |
| 2022 | 1.84 | 2.39 | 1.45 |
| 2021 | 1.86 | 2.38 | 1.47 |
| 2020 | 2.93 | 6.06 | 1.43 |
| 2019 | 1.27 | 1.6 | 0.93 |
| 2018 | 1.2 | 1.52 | 0.91 |
| 2017 | 1.68 | 1.98 | 1.27 |
| 2016 | 2.83 | 3.67 | 1.85 |
| 2015 | 3.89 | 7.04 | 2.11 |
| 2014 | 2.63 | 3.2 | 1.89 |
| 2013 | 1.77 | 2.32 | 1.3 |
| 2012 | 1.79 | 2.53 | 1.26 |
| 2011 | 2.83 | 3.76 | 2.01 |
| 2010 | 2.76 | 3.42 | 2.18 |
| 2009 | 2.08 | 3.13 | 0.96 |
| 2008 | 1.84 | 4.12 | 0.78 |
| 2007 | 2.52 | 3.62 | 1.22 |
| 2006 | 1.04 | 1.33 | 0.75 |
| 2005 | 1.05 | 1.4 | 0.83 |
| 2004 | 1.87 | 2.58 | 1.4 |
| 2003 | 2.39 | 3.06 | 1.86 |
| 2002 | 4.92 | 6.02 | 4.26 |
| 2001 | 5.9 | 6.73 | 4.81 |
| 2000 | 5.17 | 6.81 | 3.79 |
| 1999 | 4.74 | 5.64 | 3.97 |
| 1998 | 4.33 | 5.58 | 2.93 |