| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.62 | 1.9 | 1.43 |
| 2024 | 1.4 | 1.9 | 1.14 |
| 2023 | 1.62 | 1.79 | 1.44 |
| 2022 | 1.77 | 2.26 | 1.49 |
| 2021 | 2.2 | 3.5 | 1.63 |
| 2020 | 1.56 | 2.03 | 1.11 |
| 2019 | 1.59 | 2.01 | 1.35 |
| 2018 | 1.66 | 2.21 | 1.31 |
| 2017 | 2.44 | 2.78 | 2.1 |
| 2016 | 2.01 | 2.5 | 1.74 |
| 2015 | 3.41 | 5.99 | 1.98 |
| 2014 | 1.71 | 3.91 | 1.2 |
| 2013 | 1.41 | 1.73 | 1.02 |
| 2012 | 1.52 | 1.9 | 1.11 |
| 2011 | 3.17 | 6.32 | 1.43 |
| 2010 | 3.3 | 4.81 | 2.38 |
| 2009 | 4.45 | 7.05 | 3.5 |
| 2008 | 7.24 | 14.62 | 2.87 |
| 2007 | 8.66 | 15.44 | 3.44 |
| 2006 | 2.24 | 3.59 | 1.61 |
| 2005 | 2.49 | 4.01 | 1.48 |
| 2004 | 2.33 | 3.73 | 1.6 |
| 2003 | 2.13 | 2.79 | 1.71 |
| 2002 | 2.87 | 3.27 | 2.02 |
| 2001 | 3.62 | 4.22 | 2.66 |
| 2000 | 4.11 | 4.82 | 3.24 |
| 1999 | 3.52 | 5.75 | 1.88 |