| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.64 | 0.75 | 0.52 |
| 2023 | 0.76 | 0.84 | 0.65 |
| 2022 | 0.86 | 1.06 | 0.72 |
| 2021 | 1.13 | 1.55 | 0.83 |
| 2020 | 0.63 | 0.85 | 0.53 |
| 2019 | 0.64 | 0.88 | 0.53 |
| 2018 | 0.93 | 1.42 | 0.57 |
| 2017 | 1.2 | 1.68 | 0.94 |
| 2016 | 0.88 | 1.04 | 0.74 |
| 2015 | 1.12 | 1.85 | 0.85 |
| 2014 | 0.65 | 0.91 | 0.55 |
| 2013 | 0.64 | 0.76 | 0.53 |
| 2012 | 0.67 | 0.84 | 0.55 |
| 2011 | 1.04 | 1.34 | 0.7 |
| 2010 | 1.24 | 1.5 | 0.99 |
| 2009 | 1.29 | 1.72 | 0.88 |
| 2008 | 2.3 | 4.03 | 0.74 |
| 2007 | 2.51 | 3.56 | 1.24 |
| 2006 | 1.19 | 1.46 | 0.96 |
| 2005 | 0.98 | 1.17 | 0.66 |
| 2004 | 1.35 | 1.97 | 1.03 |
| 2003 | 1.76 | 2.24 | 1.38 |
| 2002 | 1.66 | 1.84 | 1.41 |
| 2001 | 2.09 | 2.62 | 1.5 |