| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.83 | 0.89 | 0.74 |
| 2024 | 0.69 | 1.04 | 0.49 |
| 2023 | 0.78 | 0.92 | 0.69 |
| 2022 | 0.76 | 0.91 | 0.64 |
| 2021 | 0.92 | 1.25 | 0.73 |
| 2020 | 0.83 | 1 | 0.75 |
| 2019 | 1.12 | 1.48 | 0.93 |
| 2018 | 1.49 | 2.18 | 0.98 |
| 2017 | 1.91 | 3.08 | 1.32 |
| 2016 | 1.57 | 2.89 | 1.17 |
| 2015 | 1.65 | 3.07 | 1.05 |
| 2014 | 0.74 | 1.19 | 0.58 |
| 2013 | 0.76 | 1.02 | 0.63 |
| 2012 | 0.99 | 1.33 | 0.71 |
| 2011 | 1.79 | 2.53 | 1.02 |
| 2010 | 2.21 | 3.47 | 1.43 |
| 2009 | 2.5 | 4.03 | 1.21 |
| 2008 | 1.94 | 3.21 | 0.69 |
| 2007 | 2 | 3 | 1.11 |
| 2006 | 0.84 | 1.04 | 0.68 |
| 2005 | 1.15 | 1.64 | 0.86 |
| 2004 | 1.92 | 3.26 | 1.35 |
| 2003 | 2.49 | 3.33 | 1.74 |
| 2002 | 1.99 | 2.32 | 1.47 |
| 2001 | 2.84 | 3.33 | 1.99 |