| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.28 | 0.32 | 0.24 |
| 2024 | 0.25 | 0.39 | 0.16 |
| 2023 | 0.34 | 0.56 | 0.22 |
| 2022 | 0.43 | 0.6 | 0.36 |
| 2021 | 0.47 | 0.59 | 0.31 |
| 2020 | 0.69 | 0.85 | 0.58 |
| 2019 | 0.69 | 0.86 | 0.56 |
| 2018 | 0.7 | 0.91 | 0.5 |
| 2017 | 1.02 | 1.44 | 0.73 |
| 2016 | 1.5 | 3.14 | 1.12 |
| 2015 | 2.21 | 3.44 | 1.3 |
| 2014 | 1.27 | 1.92 | 0.99 |
| 2013 | 1.3 | 1.7 | 1.06 |
| 2012 | 1.23 | 1.65 | 0.93 |
| 2011 | 1.84 | 2.47 | 0.95 |
| 2010 | 2.23 | 3.27 | 1.54 |
| 2009 | 2.96 | 4.24 | 1.37 |
| 2008 | 3.97 | 11.06 | 1.06 |
| 2007 | 8.29 | 14.03 | 3.22 |
| 2006 | 2.77 | 3.94 | 2.21 |
| 2005 | 2.37 | 3.53 | 1.46 |
| 2004 | 2.95 | 4.82 | 1.7 |