| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.11 | 1.28 | 0.99 |
| 2024 | 0.99 | 1.33 | 0.61 |
| 2023 | 0.88 | 0.98 | 0.8 |
| 2022 | 0.95 | 1.41 | 0.75 |
| 2021 | 1.65 | 3.07 | 1 |
| 2020 | 1.18 | 1.75 | 1.02 |
| 2019 | 1.13 | 1.44 | 0.9 |
| 2018 | 1.16 | 1.62 | 0.84 |
| 2017 | 1.77 | 2.26 | 1.36 |
| 2016 | 1.83 | 2.73 | 1.57 |
| 2015 | 2.5 | 4.03 | 1.8 |
| 2014 | 1.66 | 2.73 | 1.27 |
| 2013 | 1.36 | 1.6 | 1.14 |
| 2012 | 1.47 | 2.03 | 1.15 |
| 2011 | 2.3 | 3.11 | 1.4 |
| 2010 | 2.67 | 3.43 | 2.1 |
| 2009 | 2.26 | 3.48 | 1.01 |
| 2008 | 2.17 | 5.17 | 0.79 |
| 2007 | 3.95 | 5.65 | 1.58 |
| 2006 | 1.12 | 1.82 | 0.84 |
| 2005 | 1.09 | 1.72 | 0.68 |
| 2004 | 2.5 | 3.59 | 1.74 |
| 2003 | 2.75 | 3.14 | 2.37 |
| 2002 | 2.92 | 3.42 | 2.04 |
| 2001 | 4.06 | 5.15 | 2.41 |
| 2000 | 3.58 | 5.47 | 2.38 |