| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.87 | 1 | 0.76 |
| 2024 | 0.59 | 1.43 | 0.31 |
| 2023 | 0.56 | 0.7 | 0.37 |
| 2022 | 0.43 | 0.51 | 0.36 |
| 2021 | 0.49 | 0.64 | 0.45 |
| 2020 | 0.62 | 0.74 | 0.53 |
| 2019 | 0.68 | 0.83 | 0.52 |
| 2018 | 0.87 | 1.58 | 0.51 |
| 2017 | 1.5 | 1.68 | 1.18 |
| 2016 | 1.23 | 1.55 | 0.97 |
| 2015 | 1.59 | 2.99 | 0.82 |
| 2014 | 0.61 | 1.07 | 0.48 |
| 2013 | 0.73 | 1.08 | 0.53 |
| 2012 | 0.88 | 1.09 | 0.74 |
| 2011 | 1.54 | 2.09 | 0.79 |
| 2010 | 2.18 | 3.05 | 1.58 |
| 2009 | 2.92 | 4.27 | 1.53 |
| 2008 | 3.31 | 8.08 | 1.2 |
| 2007 | 7.2 | 13 | 2.9 |
| 2006 | 1.47 | 2.98 | 1 |
| 2005 | 0.9 | 1.1 | 0.56 |
| 2004 | 1.16 | 2.17 | 0.7 |