| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.28 | 1.35 | 1.22 |
| 2024 | 1.44 | 1.61 | 1.24 |
| 2023 | 1.79 | 2.12 | 1.35 |
| 2022 | 1.81 | 2.03 | 1.58 |
| 2021 | 2.26 | 2.6 | 2 |
| 2020 | 2.11 | 2.65 | 1.54 |
| 2019 | 1.97 | 2.16 | 1.78 |
| 2018 | 2.31 | 2.6 | 1.78 |
| 2017 | 2.48 | 2.97 | 2.23 |
| 2016 | 2.89 | 3.52 | 2.61 |
| 2015 | 3.51 | 4.99 | 2.66 |
| 2014 | 2.72 | 3.49 | 2 |
| 2013 | 3.32 | 5.08 | 2.48 |
| 2012 | 5.04 | 6.54 | 3.39 |
| 2011 | 7.07 | 8.03 | 5.96 |
| 2010 | 7.97 | 9.97 | 6.58 |
| 2009 | 5.79 | 8.41 | 3.96 |
| 2008 | 7.07 | 13.43 | 3.3 |
| 2007 | 9.48 | 11.69 | 7.8 |
| 2006 | 5.88 | 9.28 | 3.15 |
| 2005 | 1.39 | 3.36 | 0.51 |
| 2004 | 0.54 | 0.75 | 0.39 |