| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.64 | 0.66 | 0.62 |
| 2024 | 0.6 | 0.74 | 0.48 |
| 2023 | 0.64 | 0.74 | 0.56 |
| 2022 | 0.65 | 0.82 | 0.55 |
| 2021 | 0.93 | 1.17 | 0.79 |
| 2020 | 1.02 | 1.25 | 0.85 |
| 2019 | 1.11 | 1.39 | 0.77 |
| 2018 | 0.79 | 0.88 | 0.65 |
| 2017 | 1.42 | 2.27 | 0.84 |
| 2016 | 2.15 | 2.43 | 1.76 |
| 2015 | 3.15 | 6.14 | 1.83 |
| 2014 | 1.16 | 2.03 | 0.77 |
| 2013 | 1.76 | 3.13 | 1.12 |
| 2012 | 1.4 | 2.03 | 1.02 |
| 2011 | 3.3 | 5.58 | 1.56 |
| 2010 | 4.68 | 6.49 | 2.99 |
| 2009 | 4.16 | 5.14 | 3.15 |
| 2008 | 5.49 | 9.81 | 2.23 |
| 2007 | 4.54 | 5.94 | 3.12 |
| 2006 | 2.55 | 4.24 | 1.38 |
| 2005 | 1.27 | 1.83 | 0.45 |
| 2004 | 1 | 1.57 | 0.46 |