| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.47 | 0.52 | 0.4 |
| 2024 | 0.63 | 0.8 | 0.46 |
| 2023 | 0.88 | 1.08 | 0.71 |
| 2022 | 1.22 | 1.65 | 0.82 |
| 2021 | 1.54 | 10.5 | 1.2 |
| 2020 | 1.66 | 2.61 | 1.1 |
| 2019 | 1.27 | 1.68 | 0.93 |
| 2018 | 1.29 | 2.06 | 0.91 |
| 2017 | 1.84 | 2.59 | 1.01 |
| 2016 | 0.93 | 1.1 | 0.77 |
| 2015 | 1.3 | 1.95 | 0.88 |
| 2014 | 0.87 | 1.31 | 0.7 |
| 2013 | 1 | 1.46 | 0.75 |
| 2012 | 1.63 | 2.87 | 0.94 |
| 2011 | 3.36 | 5.15 | 1.68 |
| 2010 | 4.92 | 7.21 | 2.75 |
| 2009 | 5.11 | 6.17 | 3.86 |
| 2008 | 4.5 | 6.76 | 2.33 |
| 2007 | 3.81 | 5.88 | 1.88 |
| 2006 | 1.59 | 2.09 | 1.16 |
| 2005 | 1.16 | 1.46 | 0.87 |
| 2004 | 2.21 | 5.67 | 0.95 |
| 2003 | 4.43 | 5.33 | 3.35 |
| 2002 | 4.85 | 5.7 | 4.19 |
| 2001 | 6.12 | 7.5 | 3.74 |
| 2000 | 5.62 | 8.83 | 3.52 |