| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.5 | 0.53 | 0.45 |
| 2024 | 0.55 | 0.63 | 0.42 |
| 2023 | 0.75 | 0.97 | 0.6 |
| 2022 | 0.9 | 1.13 | 0.72 |
| 2021 | 0.93 | 1.1 | 0.77 |
| 2020 | 1.2 | 1.69 | 0.96 |
| 2019 | 1.18 | 1.81 | 0.99 |
| 2018 | 1.49 | 2.11 | 1.05 |
| 2017 | 1.97 | 2.32 | 1.74 |
| 2016 | 2.14 | 3.32 | 1.68 |
| 2015 | 2.93 | 4.8 | 1.74 |
| 2014 | 1.36 | 2.19 | 1.04 |
| 2013 | 1.18 | 1.37 | 0.95 |
| 2012 | 1.07 | 1.43 | 0.82 |
| 2011 | 1.27 | 1.59 | 0.85 |
| 2010 | 1.87 | 2.78 | 1.3 |
| 2009 | 1.39 | 2.78 | 0.59 |
| 2008 | 1.1 | 2.53 | 0.47 |
| 2007 | 3.06 | 4.29 | 1.79 |
| 2006 | 1.41 | 2.63 | 0.77 |
| 2005 | 0.95 | 1.24 | 0.7 |
| 2004 | 1.45 | 2.13 | 1.05 |
| 2003 | 1.94 | 2.5 | 1.37 |
| 2002 | 3.04 | 4.13 | 2.13 |
| 2001 | 4.45 | 5.91 | 3.11 |
| 2000 | 4.62 | 5.92 | 4.12 |