| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.27 | 1.35 | 1.21 |
| 2025 | 1.06 | 1.51 | 0.85 |
| 2024 | 0.97 | 1.43 | 0.74 |
| 2023 | 1.26 | 1.48 | 1.08 |
| 2022 | 1.29 | 1.7 | 1.07 |
| 2021 | 1.19 | 1.54 | 1.01 |
| 2020 | 1.11 | 1.37 | 0.95 |
| 2019 | 1.31 | 1.71 | 1.05 |
| 2018 | 1.6 | 2.39 | 1.09 |
| 2017 | 3.06 | 6.43 | 1.97 |
| 2016 | 4.9 | 5.94 | 3.89 |
| 2015 | 6.56 | 9.86 | 3.16 |
| 2014 | 3.03 | 3.5 | 2.61 |
| 2013 | 3.07 | 3.87 | 2.49 |
| 2012 | 2.95 | 3.56 | 2.32 |
| 2011 | 4.12 | 5.64 | 2.55 |
| 2010 | 3.61 | 5.99 | 1.9 |
| 2009 | 6.2 | 18.89 | 2.28 |
| 2008 | 6.49 | 13.46 | 3.59 |
| 2007 | 3.97 | 7.57 | 1.58 |
| 2006 | 1.74 | 2.18 | 1.47 |
| 2005 | 1.66 | 2.35 | 1.31 |
| 2004 | 2.23 | 3.41 | 1.51 |