| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.44 | 1.87 | 1.23 |
| 2024 | 1.22 | 1.66 | 0.98 |
| 2023 | 1.74 | 2.11 | 1.49 |
| 2022 | 2.13 | 2.59 | 1.78 |
| 2021 | 2.28 | 3.03 | 1.82 |
| 2020 | 1.79 | 2.73 | 0.95 |
| 2019 | 1.14 | 1.55 | 0.68 |
| 2018 | 1.39 | 2.27 | 0.58 |
| 2017 | 2.42 | 2.73 | 1.94 |
| 2016 | 1.52 | 2.03 | 1.19 |
| 2015 | 2.27 | 3.16 | 1.35 |
| 2014 | 1.37 | 1.76 | 1.18 |
| 2013 | 1.2 | 1.52 | 1.02 |
| 2012 | 1.42 | 1.91 | 1.07 |
| 2011 | 2.22 | 2.69 | 1.36 |
| 2010 | 2.55 | 3.09 | 2.02 |
| 2009 | 1.95 | 2.8 | 1.03 |
| 2008 | 2.17 | 3.56 | 0.91 |
| 2007 | 2.32 | 3.45 | 0.92 |
| 2006 | 0.7 | 0.98 | 0.49 |
| 2005 | 0.42 | 0.62 | 0.26 |
| 2004 | 0.41 | 0.54 | 0.3 |