| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.01 | 1.15 | 0.88 |
| 2024 | 0.86 | 1.39 | 0.61 |
| 2023 | 1.05 | 1.23 | 0.94 |
| 2022 | 1.02 | 1.59 | 0.78 |
| 2021 | 0.77 | 0.88 | 0.7 |
| 2020 | 0.82 | 1.03 | 0.68 |
| 2019 | 0.83 | 1.01 | 0.75 |
| 2018 | 0.98 | 1.22 | 0.76 |
| 2017 | 1.51 | 2.07 | 1.15 |
| 2016 | 1.65 | 2.02 | 1.33 |
| 2015 | 1.94 | 3.42 | 1.17 |
| 2014 | 1.12 | 1.52 | 0.99 |
| 2013 | 1.26 | 1.74 | 0.96 |
| 2012 | 1.29 | 1.6 | 0.94 |
| 2011 | 1.62 | 2.22 | 1 |
| 2010 | 2.27 | 3.11 | 1.74 |
| 2009 | 2.09 | 2.98 | 1.2 |
| 2008 | 1.5 | 2.81 | 0.68 |
| 2007 | 2.8 | 3.71 | 1.86 |
| 2006 | 1.64 | 1.99 | 1.3 |
| 2005 | 1.54 | 1.67 | 1.35 |
| 2004 | 1.94 | 2.65 | 1.59 |
| 2003 | 3.03 | 3.5 | 2.29 |
| 2002 | 4.85 | 10.3 | 2.98 |
| 2001 | 16.69 | 17.86 | 15.41 |
| 2000 | 17.43 | 22.77 | 8.22 |
| 1999 | 6.03 | 9.17 | 3.26 |
| 1998 | 3.59 | 4.45 | 2.9 |
| 1997 | 3.94 | 5.61 | 2.37 |