| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.51 | 0.59 | 0.45 |
| 2024 | 0.48 | 0.55 | 0.39 |
| 2023 | 0.6 | 0.68 | 0.54 |
| 2022 | 0.78 | 1.11 | 0.55 |
| 2021 | 1.04 | 1.74 | 0.66 |
| 2020 | 0.73 | 1.09 | 0.56 |
| 2019 | 0.75 | 0.96 | 0.65 |
| 2018 | 0.91 | 1.33 | 0.75 |
| 2017 | 1.45 | 2.06 | 1.2 |
| 2016 | 1.15 | 1.55 | 0.86 |
| 2015 | 1.13 | 1.39 | 0.8 |
| 2014 | 0.86 | 2.01 | 0.57 |
| 2013 | 0.97 | 1.28 | 0.79 |
| 2012 | 1.14 | 1.38 | 0.98 |
| 2011 | 1.6 | 1.7 | 1.02 |
| 2010 | 1.71 | 2.3 | 1.19 |
| 2009 | 1.92 | 2.81 | 1.13 |
| 2008 | 1.93 | 3.47 | 1.01 |
| 2007 | 2.8 | 3.87 | 1.47 |
| 2006 | 1.13 | 1.41 | 0.93 |
| 2005 | 1.31 | 1.66 | 0.9 |
| 2004 | 2.15 | 3.1 | 1.61 |
| 2003 | 2.62 | 3.07 | 2.27 |
| 2002 | 3.33 | 3.72 | 2.89 |
| 2001 | 4.35 | 5.65 | 2.97 |
| 2000 | 3.81 | 5.15 | 2.41 |