| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.54 | 0.56 | 0.49 |
| 2024 | 0.55 | 0.65 | 0.46 |
| 2023 | 0.69 | 0.87 | 0.59 |
| 2022 | 0.78 | 0.88 | 0.67 |
| 2021 | 0.69 | 0.79 | 0.62 |
| 2020 | 0.9 | 1.15 | 0.73 |
| 2019 | 1.18 | 1.42 | 1.02 |
| 2018 | 1.32 | 1.47 | 1.15 |
| 2017 | 1.58 | 1.79 | 1.39 |
| 2016 | 1.6 | 2 | 1.39 |
| 2015 | 1.94 | 2.78 | 1.53 |
| 2014 | 1.49 | 1.82 | 1.32 |
| 2013 | 1.52 | 1.79 | 1.28 |
| 2012 | 1.47 | 1.94 | 1.14 |
| 2011 | 2.23 | 2.64 | 1.53 |
| 2010 | 2.46 | 3.53 | 1.8 |
| 2009 | 2.68 | 3.52 | 2.23 |
| 2008 | 3.45 | 7.24 | 1.89 |
| 2007 | 5.66 | 9.53 | 1.8 |
| 2006 | 1.68 | 1.9 | 1.49 |
| 2005 | 1.43 | 1.82 | 1.02 |
| 2004 | 1.84 | 2.26 | 1.61 |
| 2003 | 1.43 | 1.65 | 1.29 |
| 2002 | 1.68 | 1.95 | 1.36 |
| 2001 | 1.91 | 2.1 | 1.54 |