| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.25 | 1 |
| 2024 | 1.13 | 1.51 | 0.81 |
| 2023 | 0.9 | 1.16 | 0.69 |
| 2022 | 0.91 | 1.15 | 0.7 |
| 2021 | 1.01 | 1.54 | 0.63 |
| 2020 | 0.56 | 0.95 | 0.41 |
| 2019 | 0.46 | 0.58 | 0.38 |
| 2018 | 0.6 | 1.08 | 0.39 |
| 2017 | 0.94 | 1.53 | 0.63 |
| 2016 | 0.58 | 0.79 | 0.41 |
| 2015 | 0.5 | 0.83 | 0.32 |
| 2014 | 0.33 | 0.5 | 0.26 |
| 2013 | 0.42 | 0.56 | 0.3 |
| 2012 | 0.54 | 0.74 | 0.39 |
| 2011 | 1.24 | 1.79 | 0.54 |
| 2010 | 1.8 | 3.07 | 1.26 |
| 2009 | 1.64 | 2.99 | 0.58 |
| 2008 | 1.89 | 4.59 | 0.48 |
| 2007 | 5.77 | 11.67 | 3.14 |
| 2006 | 2.45 | 3.18 | 2.03 |
| 2005 | 2.48 | 3.29 | 1.89 |
| 2004 | 3.16 | 5.11 | 2.08 |