| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.3 | 0.32 | 0.28 |
| 2024 | 0.29 | 0.42 | 0.17 |
| 2023 | 0.37 | 0.46 | 0.34 |
| 2022 | 0.38 | 0.6 | 0.32 |
| 2021 | 0.38 | 0.42 | 0.33 |
| 2020 | 0.47 | 0.56 | 0.42 |
| 2019 | 0.6 | 0.75 | 0.53 |
| 2018 | 0.77 | 1.22 | 0.53 |
| 2017 | 1.19 | 1.3 | 1.07 |
| 2016 | 1.36 | 1.96 | 1.07 |
| 2015 | 1.34 | 1.99 | 0.96 |
| 2014 | 0.76 | 1.06 | 0.65 |
| 2013 | 0.91 | 1.12 | 0.78 |
| 2012 | 1.04 | 1.3 | 0.84 |
| 2011 | 1.53 | 2.44 | 0.87 |
| 2010 | 1.87 | 2.59 | 1.38 |
| 2009 | 1.69 | 2.63 | 0.99 |
| 2008 | 2.12 | 4.52 | 0.81 |
| 2007 | 4.2 | 5.96 | 2.9 |
| 2006 | 1.78 | 3.24 | 1.38 |
| 2005 | 2.03 | 2.65 | 1.29 |
| 2004 | 2.83 | 3.53 | 2.53 |
| 2003 | 2.88 | 3.69 | 2.16 |
| 2002 | 4.1 | 4.98 | 3.32 |
| 2001 | 6.5 | 8.29 | 4.36 |
| 2000 | 6.57 | 8.19 | 5.36 |