| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.81 | 1.06 | 0.72 |
| 2024 | 0.7 | 0.86 | 0.59 |
| 2023 | 0.8 | 0.98 | 0.68 |
| 2022 | 0.83 | 1.12 | 0.63 |
| 2021 | 0.64 | 1.11 | 0.49 |
| 2020 | 0.61 | 0.82 | 0.54 |
| 2019 | 0.91 | 1.26 | 0.69 |
| 2018 | 1.29 | 1.87 | 0.86 |
| 2017 | 2.23 | 3.52 | 1.69 |
| 2016 | 1.58 | 2.24 | 1.17 |
| 2015 | 5.29 | 11.45 | 1.83 |
| 2014 | 4.01 | 6.23 | 3.1 |
| 2013 | 3.33 | 3.98 | 2.7 |
| 2012 | 3.95 | 5.58 | 2.48 |
| 2011 | 3.82 | 5.54 | 2.45 |
| 2010 | 3.62 | 4.76 | 2.75 |
| 2009 | 2.7 | 4.55 | 1.42 |
| 2008 | 3.27 | 8.05 | 1.13 |
| 2007 | 6.9 | 11.75 | 4 |
| 2006 | 4.31 | 6.18 | 2.63 |
| 2005 | 2.47 | 3.03 | 1.65 |
| 2004 | 3.05 | 5.21 | 1.95 |