| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.14 | 1.26 | 1.05 |
| 2024 | 1.05 | 1.41 | 0.85 |
| 2023 | 1.37 | 1.73 | 1.1 |
| 2022 | 1.1 | 1.42 | 0.81 |
| 2021 | 1.18 | 1.62 | 0.79 |
| 2020 | 0.69 | 1.05 | 0.53 |
| 2019 | 0.79 | 1.1 | 0.62 |
| 2018 | 0.98 | 1.62 | 0.61 |
| 2017 | 1.49 | 1.81 | 1.31 |
| 2016 | 1.46 | 1.8 | 1.32 |
| 2015 | 2.25 | 3.63 | 1.53 |
| 2014 | 1.78 | 2.29 | 1.48 |
| 2013 | 2.15 | 3.53 | 1.69 |
| 2012 | 2.32 | 2.78 | 1.91 |
| 2011 | 3.6 | 4.85 | 2.42 |
| 2010 | 3.92 | 4.81 | 2.89 |
| 2009 | 3.11 | 3.97 | 1.68 |
| 2008 | 5.63 | 18.67 | 1.3 |
| 2007 | 8.98 | 16.4 | 2.91 |
| 2006 | 2.12 | 3.02 | 1.54 |
| 2005 | 1.57 | 1.98 | 1.14 |
| 2004 | 2.39 | 3.33 | 1.81 |
| 2003 | 2.93 | 3.66 | 2.15 |