| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.03 | 1.21 | 0.9 |
| 2024 | 1.02 | 1.28 | 0.86 |
| 2023 | 1.31 | 1.77 | 0.98 |
| 2022 | 1.2 | 1.93 | 0.57 |
| 2021 | 0.65 | 1.51 | 0.45 |
| 2020 | 0.46 | 0.52 | 0.4 |
| 2019 | 0.5 | 0.68 | 0.42 |
| 2018 | 0.66 | 1 | 0.37 |
| 2017 | 1.45 | 1.99 | 0.92 |
| 2016 | 1.84 | 2.32 | 1.52 |
| 2015 | 1.81 | 3.08 | 1.1 |
| 2014 | 1.08 | 1.31 | 0.94 |
| 2013 | 1.16 | 1.42 | 0.91 |
| 2012 | 1.56 | 1.96 | 0.98 |
| 2011 | 2.47 | 3.51 | 1.54 |
| 2010 | 2.92 | 4.15 | 2.19 |
| 2009 | 1.85 | 3.24 | 0.58 |
| 2008 | 5.06 | 18.26 | 0.4 |
| 2007 | 4.13 | 6.52 | 1.78 |
| 2006 | 2 | 2.48 | 1.64 |
| 2005 | 2.4 | 3.3 | 1.76 |