| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.73 | 1.07 | 0.56 |
| 2024 | 0.61 | 0.79 | 0.45 |
| 2023 | 0.83 | 1.01 | 0.64 |
| 2022 | 1.02 | 2.18 | 0.55 |
| 2021 | 0.55 | 0.7 | 0.47 |
| 2020 | 0.69 | 0.83 | 0.62 |
| 2019 | 0.8 | 1.08 | 0.66 |
| 2018 | 0.97 | 1.33 | 0.76 |
| 2017 | 1.55 | 2.04 | 1.14 |
| 2016 | 1.36 | 1.65 | 1.02 |
| 2015 | 2.04 | 3.49 | 1.09 |
| 2014 | 1.87 | 2.61 | 1.28 |
| 2013 | 1.46 | 1.66 | 1.25 |
| 2012 | 1.42 | 1.69 | 1.25 |
| 2011 | 2.08 | 2.6 | 1.41 |
| 2010 | 3 | 4 | 2.32 |
| 2009 | 3.54 | 5.81 | 2.1 |
| 2008 | 4.56 | 8.98 | 1.98 |
| 2007 | 7.47 | 9.74 | 3.41 |
| 2006 | 1.99 | 3.86 | 0.87 |
| 2005 | 1.05 | 1.46 | 0.77 |
| 2004 | 1.87 | 2.61 | 1.32 |
| 2003 | 2.48 | 3.19 | 2.07 |
| 2002 | 3.67 | 4.16 | 2.8 |
| 2001 | 4.7 | 6.41 | 3.35 |