| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.72 | 0.78 | 0.66 |
| 2024 | 0.67 | 0.77 | 0.61 |
| 2023 | 0.86 | 1.08 | 0.64 |
| 2022 | 0.85 | 0.97 | 0.7 |
| 2021 | 1.02 | 1.26 | 0.76 |
| 2020 | 0.98 | 1.25 | 0.85 |
| 2019 | 0.99 | 1.15 | 0.72 |
| 2018 | 1.19 | 1.79 | 0.8 |
| 2017 | 1.31 | 1.96 | 0.91 |
| 2016 | 0.8 | 0.92 | 0.67 |
| 2015 | 1.04 | 1.51 | 0.78 |
| 2014 | 0.92 | 2.16 | 0.71 |
| 2013 | 0.77 | 0.93 | 0.68 |
| 2012 | 0.52 | 0.68 | 0.37 |
| 2011 | 0.78 | 1.23 | 0.47 |
| 2010 | 0.87 | 1.27 | 0.68 |
| 2009 | 1.15 | 2.8 | 0.41 |
| 2008 | 1.66 | 4.41 | 0.3 |
| 2007 | 2.44 | 4.1 | 1 |
| 2006 | 1.07 | 1.91 | 0.72 |
| 2005 | 0.41 | 0.72 | 0.22 |
| 2004 | 0.68 | 2.13 | 0.34 |
| 2003 | 0.52 | 0.79 | 0.38 |
| 2002 | 0.46 | 0.6 | 0.37 |
| 2001 | 0.67 | 1.07 | 0.29 |
| 2000 | 0.62 | 0.76 | 0.44 |
| 1999 | 0.33 | 0.67 | 0.12 |
| 1998 | 0.27 | 0.4 | 0.14 |