| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.3 | 0.35 | 0.25 |
| 2024 | 0.21 | 0.5 | 0.13 |
| 2023 | 0.27 | 0.31 | 0.22 |
| 2022 | 0.25 | 0.4 | 0.14 |
| 2021 | 0.26 | 0.51 | 0.16 |
| 2020 | 0.62 | 0.84 | 0.5 |
| 2019 | 1.04 | 1.4 | 0.78 |
| 2018 | 1.35 | 2.29 | 0.86 |
| 2017 | 1.76 | 2.44 | 1.5 |
| 2016 | 1.98 | 2.24 | 1.74 |
| 2015 | 2.47 | 3.37 | 1.79 |
| 2014 | 1.56 | 2.29 | 1.17 |
| 2013 | 2.08 | 2.7 | 1.37 |
| 2012 | 1.84 | 2.75 | 1.2 |
| 2011 | 9 | 33.52 | 1.62 |
| 2010 | 8.67 | 13.02 | 5.89 |
| 2009 | 5.11 | 9.82 | 1.81 |
| 2008 | 3.43 | 5.88 | 1.18 |
| 2007 | 4.46 | 7.53 | 2.43 |
| 2006 | 2.62 | 3.59 | 2.21 |
| 2005 | 2.16 | 2.74 | 1.28 |
| 2004 | 2.88 | 6.04 | 1.75 |