| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.78 | 0.91 | 0.68 |
| 2023 | 0.88 | 1.15 | 0.67 |
| 2022 | 1.14 | 1.69 | 0.74 |
| 2021 | 1.75 | 2 | 1.51 |
| 2020 | 1.49 | 1.79 | 1.24 |
| 2019 | 1.54 | 1.71 | 1.18 |
| 2018 | 1.51 | 2.01 | 1.19 |
| 2017 | 1.41 | 1.78 | 1.12 |
| 2016 | 1.16 | 1.25 | 1.03 |
| 2015 | 1.33 | 1.61 | 1.12 |
| 2014 | 0.97 | 1.39 | 0.86 |
| 2013 | 1.27 | 1.67 | 1 |
| 2012 | 1.4 | 1.83 | 1.11 |
| 2011 | 1.94 | 2.47 | 1.57 |
| 2010 | 2.78 | 3.98 | 2.06 |
| 2009 | 3.4 | 4.58 | 2.12 |
| 2008 | 5.07 | 10.08 | 2.04 |
| 2007 | 7.1 | 10.62 | 4.38 |
| 2006 | 3.36 | 4.81 | 2.57 |
| 2005 | 2.9 | 3.32 | 1.93 |
| 2004 | 3.31 | 4.29 | 2.75 |
| 2003 | 3.67 | 4.39 | 2.93 |