| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.2 | 1.25 | 1.14 |
| 2024 | 1.3 | 1.43 | 1.14 |
| 2023 | 1.78 | 2.22 | 1.29 |
| 2022 | 1.76 | 2.19 | 1.46 |
| 2021 | 1.58 | 2.13 | 1.06 |
| 2020 | 1.93 | 2.36 | 1.5 |
| 2019 | 2.14 | 3.03 | 1.26 |
| 2018 | 1.88 | 2.52 | 1.29 |
| 2017 | 1.98 | 2.59 | 1.51 |
| 2016 | 1.51 | 1.69 | 1.33 |
| 2015 | 1.82 | 2.74 | 1.47 |
| 2014 | 1.14 | 1.82 | 0.99 |
| 2013 | 1.08 | 1.26 | 0.92 |
| 2012 | 1.12 | 1.21 | 1 |
| 2011 | 1.38 | 1.68 | 1.06 |
| 2010 | 1.87 | 2.32 | 1.5 |
| 2009 | 1.8 | 2.14 | 1.46 |
| 2008 | 2.97 | 6.1 | 1.38 |
| 2007 | 3.87 | 5.49 | 1.89 |
| 2006 | 1.67 | 1.95 | 1.47 |
| 2005 | 2.01 | 2.29 | 1.64 |
| 2004 | 2.26 | 2.48 | 2.03 |