| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.64 | 2.1 | 1.4 |
| 2024 | 1.38 | 1.95 | 1.13 |
| 2023 | 1.66 | 1.88 | 1.5 |
| 2022 | 1.99 | 2.64 | 1.61 |
| 2021 | 2.13 | 3.32 | 1.77 |
| 2020 | 2.26 | 3.26 | 1.66 |
| 2019 | 2 | 2.58 | 1.69 |
| 2018 | 2.16 | 2.9 | 1.66 |
| 2017 | 3.47 | 4.52 | 2.64 |
| 2016 | 3.65 | 4.65 | 2.84 |
| 2015 | 4.58 | 9.29 | 2.98 |
| 2014 | 3.05 | 3.89 | 2.63 |
| 2013 | 3.61 | 5.08 | 2.83 |
| 2012 | 4.83 | 6.92 | 2.53 |
| 2011 | 3.83 | 4.4 | 2.63 |
| 2010 | 4.63 | 6.01 | 3.49 |
| 2009 | 4.26 | 6.56 | 1.69 |
| 2008 | 2.71 | 4.97 | 1.09 |
| 2007 | 3.92 | 5.72 | 2.07 |
| 2006 | 1.58 | 2.25 | 1.16 |
| 2005 | 1.41 | 1.64 | 0.63 |
| 2004 | 1.93 | 2.94 | 1.46 |
| 2003 | 3.01 | 3.73 | 2.31 |
| 2002 | 3.45 | 3.89 | 2.55 |
| 2001 | 4.03 | 4.7 | 3.11 |