| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0.7 | 1.09 | 0.18 |
| 2023 | 1.12 | 1.38 | 0.98 |
| 2022 | 1.36 | 1.9 | 0.99 |
| 2021 | 0.86 | 1.54 | 0.61 |
| 2020 | 0.8 | 0.9 | 0.69 |
| 2019 | 0.93 | 1.42 | 0.7 |
| 2018 | 0.87 | 1.19 | 0.7 |
| 2017 | 1.69 | 2.38 | 0.94 |
| 2016 | 1.55 | 2.13 | 1.32 |
| 2015 | 2.43 | 3.55 | 1.16 |
| 2014 | 1.11 | 1.44 | 0.92 |
| 2013 | 1.23 | 1.69 | 0.89 |
| 2012 | 0.77 | 0.98 | 0.6 |
| 2011 | 1.32 | 1.97 | 0.68 |
| 2010 | 1.87 | 2.83 | 1.21 |
| 2009 | 2.9 | 4.58 | 0.66 |
| 2008 | 1.13 | 2.41 | 0.42 |
| 2007 | 1.49 | 2.83 | 0.67 |
| 2006 | 0.67 | 0.8 | 0.44 |
| 2005 | 0.58 | 0.73 | 0.49 |
| 2004 | 0.9 | 1.63 | 0.57 |