| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.94 | 1 | 0.85 |
| 2024 | 0.86 | 1.18 | 0.69 |
| 2023 | 0.97 | 1.11 | 0.85 |
| 2022 | 1.06 | 1.38 | 0.93 |
| 2021 | 1.4 | 1.67 | 1.29 |
| 2020 | 1.49 | 1.91 | 1.19 |
| 2019 | 1.41 | 1.68 | 1.04 |
| 2018 | 1.25 | 1.79 | 0.85 |
| 2017 | 2.04 | 2.33 | 1.63 |
| 2016 | 2.99 | 3.97 | 2.22 |
| 2015 | 4.42 | 6.44 | 2.34 |
| 2014 | 2.31 | 6.55 | 1.53 |
| 2013 | 1.8 | 2.19 | 1.44 |
| 2012 | 1.79 | 2.11 | 1.45 |
| 2011 | 2.2 | 3.33 | 1.47 |
| 2010 | 4 | 8.21 | 2.39 |
| 2009 | 6.07 | 9.22 | 3.03 |
| 2008 | 5.06 | 8.65 | 2.94 |
| 2007 | 0 | -10.08 | |
| 2006 | 7.77 | 12.22 | 4.08 |
| 2005 | 2.32 | 4.26 | 1.25 |
| 2004 | 3.38 | 4.7 | 2.25 |
| 2003 | 3.04 | 3.79 | 2.56 |
| 2002 | 3.18 | 4.17 | 1.96 |
| 2001 | 3.49 | 4.09 | 2.83 |
| 2000 | 3.07 | 3.93 | 2.16 |
| 1999 | 2.76 | 3.84 | 2.1 |
| 1998 | 3.92 | 5.31 | 2.91 |