| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.05 | 1.15 | 0.98 |
| 2024 | 1.13 | 1.46 | 0.92 |
| 2023 | 1.06 | 1.17 | 0.92 |
| 2022 | 1.03 | 1.18 | 0.84 |
| 2021 | 0.89 | 1.28 | 0.65 |
| 2020 | 0.75 | 0.9 | 0.7 |
| 2019 | 0.91 | 1.17 | 0.76 |
| 2018 | 1.12 | 1.45 | 0.89 |
| 2017 | 1.46 | 1.73 | 1.22 |
| 2016 | 1.57 | 2.05 | 1.35 |
| 2015 | 3.17 | 5.44 | 1.58 |
| 2014 | 1.92 | 2.6 | 1.37 |
| 2013 | 1.97 | 3.1 | 1.35 |
| 2012 | 3.49 | 4.9 | 2.21 |
| 2011 | 6.41 | 9.08 | 4.64 |
| 2010 | 7.32 | 10.81 | 4.4 |
| 2009 | 7.75 | 11.49 | 5.22 |
| 2008 | 9.91 | 17.87 | 3.96 |
| 2007 | 13.96 | 19.17 | 6.93 |
| 2006 | 5.66 | 7.71 | 2.59 |
| 2005 | 2.46 | 3.29 | 1.7 |
| 2004 | 2.89 | 3.65 | 1.83 |
| 2003 | 2.67 | 3.7 | 1.89 |