| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.63 | 0.78 | 0.44 |
| 2023 | 0.75 | 0.87 | 0.65 |
| 2022 | 0.75 | 1.02 | 0.57 |
| 2021 | 1.15 | 1.65 | 0.77 |
| 2020 | 0.99 | 1.29 | 0.78 |
| 2019 | 1.13 | 1.58 | 0.84 |
| 2018 | 2.17 | 3.35 | 1.17 |
| 2017 | 2.62 | 4.16 | 1.78 |
| 2016 | 1.99 | 3.06 | 1.05 |
| 2015 | 1.17 | 1.63 | 0.83 |
| 2014 | 0.65 | 1.27 | 0.5 |
| 2013 | 0.59 | 0.68 | 0.49 |
| 2012 | 0.61 | 0.69 | 0.52 |
| 2011 | 0.83 | 1.23 | 0.59 |
| 2010 | 0.94 | 1.44 | 0.7 |
| 2009 | 1.3 | 1.96 | 0.85 |
| 2008 | 1.52 | 3.38 | 0.61 |
| 2007 | 2.03 | 3.01 | 1.03 |
| 2006 | 1.01 | 1.63 | 0.83 |
| 2005 | 1.11 | 1.39 | 0.91 |
| 2004 | 1.57 | 2.69 | 1.18 |
| 2003 | 2.28 | 2.54 | 2.03 |
| 2002 | 2.59 | 3.14 | 2.16 |
| 2001 | 3.14 | 3.66 | 2.39 |
| 2000 | 3.3 | 4.03 | 2.46 |