| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.07 | 1.24 | 0.87 |
| 2024 | 0.8 | 1.12 | 0.59 |
| 2023 | 0.83 | 0.95 | 0.61 |
| 2022 | 0.69 | 0.86 | 0.56 |
| 2021 | 0.74 | 1.24 | 0.52 |
| 2020 | 0.68 | 0.8 | 0.61 |
| 2019 | 0.8 | 0.95 | 0.68 |
| 2018 | 0.95 | 1.43 | 0.69 |
| 2017 | 1.35 | 1.76 | 1.12 |
| 2016 | 1.43 | 2.03 | 0.9 |
| 2015 | 1.24 | 1.76 | 0.96 |
| 2014 | 0.87 | 1.41 | 0.53 |
| 2013 | 0.64 | 0.9 | 0.51 |
| 2012 | 0.83 | 1.05 | 0.62 |
| 2011 | 1.3 | 1.79 | 0.92 |
| 2010 | 1.3 | 1.58 | 1.05 |
| 2009 | 1.35 | 2.07 | 0.77 |
| 2008 | 1.56 | 3.39 | 0.63 |
| 2007 | 2.3 | 3.34 | 1.15 |
| 2006 | 1.05 | 2.65 | 0.81 |
| 2005 | 0.7 | 0.95 | 0.55 |
| 2004 | 0.87 | 1.19 | 0.67 |
| 2003 | 0.96 | 1.08 | 0.87 |
| 2002 | 1.27 | 1.5 | 0.92 |
| 2001 | 1.52 | 1.82 | 1.11 |
| 2000 | 1.55 | 2.27 | 1.07 |
| 1999 | 1.29 | 1.69 | 1.06 |