| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.95 | 0.99 | 0.88 |
| 2024 | 1.09 | 1.26 | 0.94 |
| 2023 | 1.24 | 1.5 | 1.1 |
| 2022 | 1.96 | 2.89 | 1.26 |
| 2021 | 1.8 | 2.92 | 1.49 |
| 2020 | 1.4 | 2.11 | 1.12 |
| 2019 | 1.32 | 1.52 | 1.17 |
| 2018 | 1.5 | 1.91 | 1.21 |
| 2017 | 2.03 | 2.52 | 1.61 |
| 2016 | 2.6 | 3.41 | 2.12 |
| 2015 | 2.98 | 4.45 | 1.72 |
| 2014 | 1.71 | 2.87 | 1.13 |
| 2013 | 2.46 | 3.77 | 1.61 |
| 2012 | 3.9 | 4.98 | 2.72 |
| 2011 | 5.16 | 7.16 | 3.13 |
| 2010 | 4.7 | 6.37 | 3.25 |
| 2009 | 5.51 | 10.57 | 3.38 |
| 2008 | 4.96 | 7.35 | 2.62 |
| 2007 | 2.65 | 4.81 | 1.19 |
| 2006 | 1.29 | 1.91 | 1.02 |
| 2005 | 1.21 | 1.69 | 0.87 |
| 2004 | 2.17 | 2.88 | 1.63 |
| 2003 | 2.16 | 2.58 | 1.78 |
| 2002 | 3.05 | 3.33 | 2.7 |