| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.16 | 1.3 | 1.09 |
| 2024 | 1.14 | 1.36 | 0.89 |
| 2023 | 1.23 | 1.53 | 0.95 |
| 2022 | 0.98 | 1.16 | 0.84 |
| 2021 | 0.95 | 1.14 | 0.76 |
| 2020 | 0.81 | 1.05 | 0.57 |
| 2019 | 0.92 | 1.27 | 0.64 |
| 2018 | 1.53 | 2.49 | 0.71 |
| 2017 | 2.41 | 3.08 | 2.24 |
| 2016 | 3.2 | 4.99 | 2.01 |
| 2015 | 5.3 | 8.27 | 3.48 |
| 2014 | 3.86 | 6.33 | 2.98 |
| 2013 | 3.3 | 4.19 | 2.83 |
| 2012 | 3.38 | 4.88 | 2.63 |
| 2011 | 3.4 | 4.96 | 2.49 |
| 2010 | 3.51 | 5.25 | 2.36 |
| 2009 | 4.29 | 7.12 | 1.59 |
| 2008 | 2.37 | 4.21 | 1.06 |
| 2007 | 2.64 | 4.35 | 1.04 |
| 2006 | 1.08 | 1.45 | 0.83 |
| 2005 | 0.95 | 1.19 | 0.76 |
| 2004 | 1.5 | 2.07 | 1.06 |
| 2003 | 1.91 | 2.43 | 1.38 |
| 2002 | 3.4 | 4.19 | 2.99 |