| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.57 | 0.63 | 0.49 |
| 2024 | 0.54 | 0.63 | 0.43 |
| 2023 | 0.83 | 1.07 | 0.59 |
| 2022 | 1.15 | 1.85 | 0.78 |
| 2021 | 3.21 | 6.79 | 1.79 |
| 2020 | 2.16 | 3.39 | 1.01 |
| 2019 | 1.28 | 1.68 | 1.04 |
| 2018 | 1.12 | 1.43 | 0.92 |
| 2017 | 1.85 | 2.57 | 1.24 |
| 2016 | 2.65 | 3.95 | 2.2 |
| 2015 | 3.31 | 5.19 | 1.73 |
| 2014 | 2.01 | 2.64 | 1.08 |
| 2013 | 1.11 | 1.35 | 0.91 |
| 2012 | 1.29 | 1.85 | 0.96 |
| 2011 | 3.04 | 4.25 | 1.43 |
| 2010 | 4.9 | 7.11 | 3.84 |
| 2009 | 3.77 | 5.34 | 1.58 |
| 2008 | 2.69 | 5.66 | 1.26 |
| 2007 | 4.99 | 8.82 | 2.06 |
| 2006 | 2.27 | 2.93 | 1.81 |
| 2005 | 1.96 | 2.61 | 1.2 |
| 2004 | 1.6 | 2.45 | 1.18 |