| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.63 | 0.71 | 0.58 |
| 2024 | 0.57 | 0.73 | 0.47 |
| 2023 | 0.71 | 0.86 | 0.62 |
| 2022 | 0.86 | 1.35 | 0.67 |
| 2021 | 1.27 | 1.58 | 1.05 |
| 2020 | 1.7 | 2.51 | 1.22 |
| 2019 | 1.49 | 2.07 | 1.22 |
| 2018 | 2.6 | 4.49 | 1.41 |
| 2017 | 4.1 | 4.74 | 3.59 |
| 2016 | 3.48 | 4.67 | 2.25 |
| 2015 | 3.08 | 5.39 | 1.49 |
| 2014 | 1.25 | 1.65 | 1.02 |
| 2013 | 1.14 | 1.27 | 1.02 |
| 2012 | 1.18 | 1.43 | 0.96 |
| 2011 | 1.74 | 2.3 | 1.14 |
| 2010 | 2.42 | 3.4 | 1.78 |
| 2009 | 2.17 | 3.25 | 1.11 |
| 2008 | 2.23 | 4.69 | 0.88 |
| 2007 | 5.01 | 7.51 | 2.98 |
| 2006 | 2.26 | 3.37 | 1.09 |
| 2005 | 1.06 | 1.38 | 0.83 |
| 2004 | 1.66 | 2.28 | 1.31 |
| 2003 | 2.18 | 2.56 | 1.76 |
| 2002 | 2.84 | 3.12 | 2.28 |
| 2001 | 4.08 | 5.32 | 2.71 |
| 2000 | 4.16 | 4.71 | 3.11 |