| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.51 | 0.53 | 0.47 |
| 2024 | 0.52 | 0.62 | 0.42 |
| 2023 | 0.58 | 0.68 | 0.5 |
| 2022 | 0.77 | 1.15 | 0.59 |
| 2021 | 1.05 | 1.32 | 0.82 |
| 2020 | 1.06 | 1.41 | 0.87 |
| 2019 | 1.29 | 2.49 | 0.85 |
| 2018 | 1.13 | 1.4 | 0.9 |
| 2017 | 2.57 | 8.54 | 1.18 |
| 2016 | 2.85 | 8.64 | 2.2 |
| 2015 | 3.42 | 4.98 | 2.86 |
| 2014 | 2.5 | 4.9 | 1.67 |
| 2013 | 1.66 | 2.19 | 1.16 |
| 2012 | 1.33 | 1.62 | 1.04 |
| 2011 | 2.09 | 2.77 | 1.37 |
| 2010 | 2.62 | 3.55 | 1.82 |
| 2009 | 2.71 | 3.76 | 1.38 |
| 2008 | 2.73 | 4.34 | 0.99 |
| 2007 | 3.39 | 5.36 | 1.23 |
| 2006 | 1.24 | 1.57 | 0.96 |
| 2005 | 1.25 | 1.65 | 0.9 |
| 2004 | 2.06 | 2.9 | 1.51 |
| 2003 | 2.84 | 3.22 | 2.28 |
| 2002 | 3.9 | 4.98 | 2.71 |
| 2001 | 5.87 | 7.51 | 4.01 |