| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.86 | 1 | 0.73 |
| 2024 | 1.05 | 1.58 | 0.75 |
| 2023 | 2.31 | 3.87 | 1.28 |
| 2022 | 2.38 | 3.89 | 1.09 |
| 2021 | 1.9 | 3.1 | 1.18 |
| 2020 | 1.54 | 2.09 | 1.26 |
| 2019 | 1.93 | 2.66 | 1.48 |
| 2018 | 3 | 4.86 | 1.89 |
| 2017 | 5.24 | 6.28 | 3.97 |
| 2016 | 6.87 | 8.78 | 5.82 |
| 2015 | 7.17 | 14.15 | 3.05 |
| 2014 | 2.74 | 4.52 | 1.92 |
| 2013 | 2.34 | 2.82 | 2.1 |
| 2012 | 2.36 | 3.14 | 1.86 |
| 2011 | 4.33 | 5.92 | 2.28 |
| 2010 | 5.49 | 7.3 | 4.68 |
| 2009 | 3.8 | 5.97 | 1.91 |
| 2008 | 3.15 | 5.26 | 1.52 |
| 2007 | 4.04 | 6 | 1.61 |
| 2006 | 1.71 | 2.1 | 1.44 |
| 2005 | 1.53 | 1.96 | 1.02 |
| 2004 | 1.91 | 3.41 | 1.27 |