| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.63 | 0.76 | 0.56 |
| 2024 | 0.55 | 0.71 | 0.46 |
| 2023 | 0.71 | 0.79 | 0.63 |
| 2022 | 0.73 | 1.1 | 0.62 |
| 2021 | 0.76 | 0.95 | 0.64 |
| 2020 | 0.95 | 1.39 | 0.68 |
| 2019 | 0.81 | 0.99 | 0.7 |
| 2018 | 1.01 | 1.42 | 0.65 |
| 2017 | 1.68 | 2.28 | 1.36 |
| 2016 | 1.78 | 2.19 | 1.39 |
| 2015 | 1.79 | 2.75 | 1.19 |
| 2014 | 1.44 | 1.82 | 1.13 |
| 2013 | 1.16 | 1.46 | 0.93 |
| 2012 | 1.37 | 1.91 | 0.97 |
| 2011 | 2.2 | 2.93 | 1.45 |
| 2010 | 2.17 | 2.75 | 1.54 |
| 2009 | 2.18 | 3.23 | 1.38 |
| 2008 | 1.72 | 2.9 | 0.87 |
| 2007 | 2.72 | 4.33 | 1.8 |
| 2006 | 1.62 | 2.18 | 1.33 |
| 2005 | 1.33 | 1.5 | 1.09 |
| 2004 | 1.89 | 2.65 | 1.4 |
| 2003 | 2.65 | 3.27 | 2.12 |
| 2002 | 3.84 | 4.33 | 2.89 |
| 2001 | 5.66 | 6.96 | 3.87 |
| 2000 | 5.41 | 6.7 | 3.27 |
| 1999 | 3.6 | 4.55 | 2.76 |
| 1998 | 5.23 | 6.99 | 3.42 |