| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.27 | 1.5 | 1.1 |
| 2024 | 1.13 | 1.37 | 0.94 |
| 2023 | 1.36 | 1.45 | 1.25 |
| 2022 | 1.37 | 1.69 | 1.22 |
| 2021 | 1.45 | 1.94 | 1.26 |
| 2020 | 1.55 | 1.9 | 1.35 |
| 2019 | 1.58 | 1.97 | 1.3 |
| 2018 | 1.72 | 2.5 | 1.27 |
| 2017 | 2.99 | 3.65 | 2.31 |
| 2016 | 3.74 | 4.59 | 3.33 |
| 2015 | 4.23 | 6.1 | 3.21 |
| 2014 | 3.98 | 5.21 | 3.13 |
| 2013 | 3.16 | 4 | 2.22 |
| 2012 | 3.58 | 6.2 | 1.85 |
| 2011 | 6.78 | 10.06 | 5.01 |
| 2010 | 6.13 | 10.32 | 4.4 |
| 2009 | 3.41 | 4.98 | 2.06 |
| 2008 | 2.95 | 5.01 | 1.6 |
| 2007 | 3.7 | 5.12 | 2.43 |
| 2006 | 2.3 | 2.79 | 1.73 |
| 2005 | 1.87 | 2.57 | 1.44 |
| 2004 | 1.96 | 2.84 | 1.53 |
| 2003 | 2.74 | 3.23 | 2.01 |
| 2002 | 3.96 | 4.98 | 2.87 |
| 2001 | 5.59 | 6.46 | 4.84 |