| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.91 | 1.07 | 0.85 |
| 2024 | 1.02 | 1.25 | 0.84 |
| 2023 | 1.16 | 1.36 | 1.03 |
| 2022 | 0.9 | 1.18 | 0.75 |
| 2021 | 0.89 | 1.07 | 0.79 |
| 2020 | 1.01 | 1.61 | 0.81 |
| 2019 | 1.13 | 1.48 | 0.95 |
| 2018 | 1.15 | 1.42 | 0.95 |
| 2017 | 1.29 | 1.58 | 1.14 |
| 2016 | 1.38 | 1.75 | 1.23 |
| 2015 | 2.43 | 3.62 | 1.71 |
| 2014 | 2.07 | 2.58 | 1.81 |
| 2013 | 2.61 | 3.33 | 2.21 |
| 2012 | 2.36 | 2.67 | 1.97 |
| 2011 | 2.96 | 3.99 | 2.21 |
| 2010 | 3.17 | 4.49 | 2 |
| 2009 | 5.3 | 8.38 | 3.9 |
| 2008 | 9.68 | 15.62 | 4.67 |
| 2007 | 11.72 | 15.89 | 8.75 |
| 2006 | 6.65 | 10.12 | 4.2 |
| 2005 | 4.66 | 5.37 | 3.68 |
| 2004 | 3.45 | 4.39 | 2.71 |
| 2003 | 2.78 | 3.12 | 2.53 |