| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.37 | 0.39 | 0.34 |
| 2024 | 0.33 | 0.51 | 0.24 |
| 2023 | 0.43 | 0.54 | 0.31 |
| 2022 | 0.48 | 0.68 | 0.34 |
| 2021 | 0.8 | 1.29 | 0.5 |
| 2020 | 0.97 | 1.2 | 0.81 |
| 2019 | 1.18 | 1.53 | 1.03 |
| 2018 | 1.47 | 2.47 | 0.96 |
| 2017 | 1.92 | 2.29 | 1.64 |
| 2016 | 1.76 | 2.3 | 1.55 |
| 2015 | 2.26 | 3.45 | 1.71 |
| 2014 | 1.27 | 1.99 | 1.08 |
| 2013 | 1.85 | 2.94 | 1.27 |
| 2012 | 2.38 | 2.94 | 2.05 |
| 2011 | 2.4 | 2.9 | 1.91 |
| 2010 | 5.24 | 12.2 | 2.16 |
| 2009 | 12.78 | 18.47 | 8.39 |
| 2008 | 18.07 | 36.5 | 7.31 |
| 2007 | 30.69 | 42.91 | 16.17 |
| 2006 | 22.03 | 32.47 | 16.86 |
| 2005 | 15.94 | 23.31 | 7.67 |
| 2004 | 9.63 | 15.74 | 7.19 |