| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.72 | 0.74 | 0.7 |
| 2024 | 0.73 | 0.86 | 0.64 |
| 2023 | 0.72 | 0.81 | 0.66 |
| 2022 | 0.8 | 0.99 | 0.67 |
| 2021 | 0.91 | 1.2 | 0.81 |
| 2020 | 0.97 | 1.14 | 0.8 |
| 2019 | 1.27 | 1.91 | 1.05 |
| 2018 | 1.76 | 2.57 | 1.14 |
| 2017 | 2.8 | 4.12 | 2.09 |
| 2016 | 2.31 | 2.81 | 1.98 |
| 2015 | 4.06 | 6.81 | 2.27 |
| 2014 | 2.67 | 4.64 | 2.18 |
| 2013 | 2.7 | 3.36 | 1.76 |
| 2012 | 1.98 | 2.45 | 1.58 |
| 2011 | 2.57 | 3.16 | 2.05 |
| 2010 | 3.09 | 3.95 | 2.43 |
| 2009 | 3.09 | 3.69 | 2.21 |
| 2008 | 4.62 | 10.73 | 1.8 |
| 2007 | 6.28 | 11.4 | 2.84 |
| 2006 | 2.51 | 3.19 | 1.9 |
| 2005 | 2.33 | 2.84 | 1.12 |
| 2004 | 2.61 | 3.28 | 2.04 |
| 2003 | 2.84 | 3.19 | 2.55 |
| 2002 | 3.71 | 4.29 | 3.3 |
| 2001 | 5.07 | 6.35 | 3.19 |