| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.68 | 0.9 | 0.36 |
| 2024 | 0.83 | 1.18 | 0.58 |
| 2023 | 0.52 | 1.91 | 0.12 |
| 2022 | 1.39 | 2.06 | 0.46 |
| 2021 | 0.46 | 0.52 | 0.41 |
| 2020 | 0.5 | 0.6 | 0.41 |
| 2019 | 0.79 | 0.97 | 0.55 |
| 2018 | 1.17 | 1.85 | 0.8 |
| 2017 | 2.52 | 3.42 | 1.83 |
| 2016 | 3.73 | 4.51 | 3.11 |
| 2015 | 3.45 | 5.46 | 2.57 |
| 2014 | 2.54 | 3.12 | 2.2 |
| 2013 | 3.02 | 3.56 | 2.36 |
| 2012 | 3.42 | 4.58 | 2.63 |
| 2011 | 5.71 | 7.32 | 4.22 |
| 2010 | 6.21 | 8.16 | 5.06 |
| 2009 | 5.76 | 7.66 | 2.87 |
| 2008 | 7.18 | 15.26 | 2.5 |
| 2007 | 12.25 | 19.7 | 7.51 |
| 2006 | 6.02 | 7.59 | 4.33 |
| 2005 | 0.92 | 4.55 | 0.09 |
| 2004 | 0.14 | 0.25 | 0.1 |