| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.97 | 1.02 | 0.88 |
| 2023 | 0.97 | 1.08 | 0.91 |
| 2022 | 0.96 | 1.14 | 0.84 |
| 2021 | 1.17 | 1.54 | 1 |
| 2020 | 1.25 | 1.4 | 1.1 |
| 2019 | 1.64 | 2.32 | 1.3 |
| 2018 | 2.19 | 2.95 | 1.47 |
| 2017 | 3.26 | 5.08 | 2.22 |
| 2016 | 2.69 | 4.04 | 2.2 |
| 2015 | 5.54 | 8.48 | 3.35 |
| 2014 | 3.68 | 5.78 | 3.05 |
| 2013 | 4.21 | 5.42 | 2.53 |
| 2012 | 2.99 | 3.79 | 2.27 |
| 2011 | 4.2 | 5.32 | 3.18 |
| 2010 | 5.91 | 9.51 | 4.42 |
| 2009 | 8.15 | 10.1 | 6.55 |
| 2008 | 15.69 | 38.79 | 5.34 |
| 2007 | 24.51 | 41.27 | 13.36 |
| 2006 | 19.78 | 33.19 | 10.66 |
| 2005 | 25.42 | 32.01 | 13.53 |
| 2004 | 36.35 | 58.8 | 19.01 |