| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.97 | 1.33 | 0.69 |
| 2023 | 0.84 | 1.11 | 0.46 |
| 2022 | 1.16 | 1.69 | 0.66 |
| 2021 | 0.45 | 0.99 | 0.2 |
| 2020 | 0.23 | 0.28 | 0.2 |
| 2019 | 0.29 | 0.37 | 0.23 |
| 2018 | 0.42 | 0.62 | 0.28 |
| 2017 | 0.47 | 0.59 | 0.37 |
| 2016 | 0.78 | 1.04 | 0.54 |
| 2015 | 1.03 | 1.64 | 0.66 |
| 2014 | 0.63 | 1.03 | 0.48 |
| 2013 | 1.11 | 1.66 | 0.73 |
| 2012 | 2 | 3.05 | 1.3 |
| 2011 | 4.04 | 5.52 | 2.4 |
| 2010 | 4.28 | 5.72 | 3.08 |
| 2009 | 3.45 | 5.82 | 1.69 |
| 2008 | 4.53 | 7.57 | 1.58 |
| 2007 | 5.41 | 9.13 | 2.73 |
| 2006 | 2.63 | 3.49 | 2.28 |
| 2005 | 1.53 | 2.24 | 0.86 |
| 2004 | 1.99 | 3.2 | 1.28 |