| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.07 | 1.38 | 0.84 |
| 2024 | 0.83 | 0.95 | 0.69 |
| 2023 | 0.92 | 1.06 | 0.83 |
| 2022 | 0.96 | 1.39 | 0.8 |
| 2021 | 1.45 | 1.83 | 1.15 |
| 2020 | 1.58 | 2.05 | 1.15 |
| 2019 | 2.48 | 5.62 | 1.21 |
| 2018 | 2.15 | 3.1 | 1.46 |
| 2017 | 3.08 | 3.59 | 2.72 |
| 2016 | 4.14 | 8.46 | 2.83 |
| 2015 | 4.57 | 9.3 | 2.3 |
| 2014 | 2.77 | 4.34 | 1.93 |
| 2013 | 2.07 | 2.43 | 1.72 |
| 2012 | 2.08 | 2.58 | 1.49 |
| 2011 | 3.62 | 4.77 | 2.1 |
| 2010 | 4.2 | 5.73 | 2.91 |
| 2009 | 2.92 | 4.1 | 1.82 |
| 2008 | 2.61 | 4.81 | 1.29 |
| 2007 | 3.58 | 5.34 | 1.49 |
| 2006 | 1.55 | 1.96 | 1.18 |
| 2005 | 1.19 | 1.41 | 0.95 |
| 2004 | 1.91 | 2.94 | 1.2 |
| 2003 | 2.6 | 3.37 | 1.92 |
| 2002 | 4.6 | 5.17 | 4.14 |
| 2001 | 6.25 | 7.66 | 4.26 |