| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.17 | 1.24 | 1.11 |
| 2024 | 1.15 | 1.29 | 0.99 |
| 2023 | 0.97 | 1.13 | 0.85 |
| 2022 | 0.94 | 1.13 | 0.8 |
| 2021 | 0.94 | 1.26 | 0.8 |
| 2020 | 0.91 | 1 | 0.84 |
| 2019 | 0.99 | 1.11 | 0.87 |
| 2018 | 0.96 | 1.09 | 0.86 |
| 2017 | 1.09 | 1.17 | 1 |
| 2016 | 1.13 | 1.42 | 1.05 |
| 2015 | 1.67 | 2.7 | 1.21 |
| 2014 | 0.99 | 1.42 | 0.87 |
| 2013 | 1.03 | 1.14 | 0.87 |
| 2012 | 1.09 | 1.24 | 0.95 |
| 2011 | 1.35 | 1.78 | 1.08 |
| 2010 | 1.77 | 2.28 | 1.45 |
| 2009 | 2.07 | 2.88 | 1.29 |
| 2008 | 2.17 | 4.2 | 1.1 |
| 2007 | 3.53 | 4.86 | 1.85 |
| 2006 | 1.56 | 1.84 | 1.36 |
| 2005 | 1.88 | 2.29 | 1.37 |
| 2004 | 2.81 | 4.47 | 1.65 |
| 2003 | 3.43 | 4.36 | 2.33 |
| 2002 | 3.2 | 4.47 | 2.43 |
| 2001 | 5.74 | 6.89 | 4.29 |
| 2000 | 5.54 | 7.28 | 3.89 |
| 1999 | 4.38 | 5.65 | 2.88 |
| 1998 | 4.64 | 6.52 | 3.3 |
| 1997 | 5.45 | 7.67 | 4.02 |