| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.72 | 0.82 | 0.62 |
| 2023 | 0.7 | 0.8 | 0.62 |
| 2022 | 0.71 | 0.91 | 0.55 |
| 2021 | 0.94 | 1.38 | 0.73 |
| 2020 | 0.66 | 0.81 | 0.56 |
| 2019 | 0.82 | 1.04 | 0.67 |
| 2018 | 1.12 | 1.59 | 0.82 |
| 2017 | 1.09 | 1.37 | 0.84 |
| 2016 | 0.77 | 1 | 0.7 |
| 2015 | 0.99 | 1.4 | 0.74 |
| 2014 | 0.64 | 1.04 | 0.54 |
| 2013 | 0.68 | 0.78 | 0.57 |
| 2012 | 0.75 | 0.88 | 0.66 |
| 2011 | 1 | 1.28 | 0.77 |
| 2010 | 1.26 | 1.79 | 1.03 |
| 2009 | 1.31 | 1.92 | 0.88 |
| 2008 | 1.96 | 3.96 | 0.77 |
| 2007 | 2.81 | 4.48 | 1.84 |
| 2006 | 1.09 | 1.94 | 0.93 |
| 2005 | 1.6 | 2.08 | 0.92 |
| 2004 | 2.24 | 3.07 | 1.83 |
| 2003 | 2.33 | 2.94 | 2.01 |
| 2002 | 2.04 | 2.18 | 1.89 |
| 2001 | 2.45 | 3.19 | 1.81 |