| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.93 | 1.12 | 0.86 |
| 2024 | 1.06 | 1.43 | 0.79 |
| 2023 | 1.48 | 1.87 | 1.2 |
| 2022 | 1.98 | 2.57 | 1.62 |
| 2021 | 2.03 | 4.17 | 0.94 |
| 2020 | 1.08 | 1.44 | 0.89 |
| 2019 | 1.36 | 2.09 | 1.14 |
| 2018 | 2.14 | 3.3 | 1.33 |
| 2017 | 3.21 | 4.61 | 2.5 |
| 2016 | 2.15 | 2.75 | 1.84 |
| 2015 | 2.94 | 4.71 | 2.06 |
| 2014 | 1.53 | 2.2 | 1.03 |
| 2013 | 1.09 | 1.35 | 0.86 |
| 2012 | 1.22 | 1.77 | 0.92 |
| 2011 | 2.29 | 3.04 | 1.32 |
| 2010 | 1.88 | 2.29 | 1.36 |
| 2009 | 1.68 | 2.26 | 1.08 |
| 2008 | 2.33 | 4.87 | 0.94 |
| 2007 | 3.15 | 4.53 | 1.32 |
| 2006 | 1.25 | 1.49 | 1.1 |
| 2005 | 1.48 | 1.91 | 0.94 |
| 2004 | 1.91 | 2.54 | 1.54 |
| 2003 | 1.94 | 2.26 | 1.56 |
| 2002 | 2.7 | 3.91 | 1.84 |
| 2001 | 4.66 | 5.67 | 3.87 |
| 2000 | 3.76 | 5.38 | 2.74 |
| 1999 | 2.83 | 3.65 | 2.41 |