| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.53 | 0.7 |
| 2024 | 0.61 | 1 | 0.43 |
| 2023 | 0.49 | 0.59 | 0.42 |
| 2022 | 0.49 | 0.72 | 0.4 |
| 2021 | 0.65 | 1.05 | 0.38 |
| 2020 | 0.83 | 1.18 | 0.53 |
| 2019 | 0.88 | 1.46 | 0.59 |
| 2018 | 1.37 | 2.63 | 0.73 |
| 2017 | 1.99 | 2.82 | 1.57 |
| 2016 | 2.58 | 3.66 | 1.62 |
| 2015 | 2.85 | 5.9 | 1.51 |
| 2014 | 1.28 | 1.9 | 0.96 |
| 2013 | 1.61 | 2.19 | 1.38 |
| 2012 | 1.77 | 2.34 | 0.97 |
| 2011 | 1.29 | 1.66 | 0.94 |
| 2010 | 1.67 | 2.47 | 1.04 |
| 2009 | 2.01 | 3.13 | 1.21 |
| 2008 | 1.9 | 3.2 | 0.94 |
| 2007 | 2.97 | 5.13 | 1.16 |
| 2006 | 1.23 | 2.1 | 0.88 |
| 2005 | 1.45 | 1.76 | 1.18 |
| 2004 | 2.11 | 4.44 | 1.25 |