| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.9 | 0.99 | 0.81 |
| 2024 | 0.66 | 1.27 | 0.46 |
| 2023 | 0.63 | 0.76 | 0.5 |
| 2022 | 0.6 | 0.92 | 0.47 |
| 2021 | 0.48 | 0.58 | 0.42 |
| 2020 | 0.53 | 0.66 | 0.43 |
| 2019 | 0.6 | 0.79 | 0.5 |
| 2018 | 0.66 | 0.92 | 0.5 |
| 2017 | 0.87 | 1.07 | 0.7 |
| 2016 | 1 | 1.42 | 0.84 |
| 2015 | 1.57 | 3.09 | 0.75 |
| 2014 | 0.61 | 0.85 | 0.39 |
| 2013 | 0.38 | 0.48 | 0.29 |
| 2012 | 0.4 | 0.51 | 0.32 |
| 2011 | 0.82 | 1.36 | 0.42 |
| 2010 | 2.17 | 3.23 | 1.12 |
| 2009 | 2.15 | 3.15 | 0.97 |
| 2008 | 1.94 | 4.14 | 0.74 |
| 2007 | 3.45 | 5.63 | 1.92 |
| 2006 | 1.27 | 1.86 | 0.91 |
| 2005 | 0.95 | 1.21 | 0.64 |
| 2004 | 1.1 | 2.01 | 0.7 |