| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.16 | 1.25 | 1.07 |
| 2024 | 1.12 | 1.34 | 0.89 |
| 2023 | 1.47 | 1.74 | 1.17 |
| 2022 | 1.94 | 2.76 | 1.51 |
| 2021 | 2.34 | 3.56 | 1.53 |
| 2020 | 1.71 | 2.3 | 1.48 |
| 2019 | 2.7 | 4.75 | 1.66 |
| 2018 | 4.29 | 7.63 | 2.63 |
| 2017 | 5.17 | 10.67 | 2.55 |
| 2016 | 2.91 | 3.41 | 2.37 |
| 2015 | 3.43 | 5.1 | 2 |
| 2014 | 2.7 | 3.5 | 2.02 |
| 2013 | 3.33 | 4.57 | 2.26 |
| 2012 | 3.45 | 4.62 | 2.43 |
| 2011 | 5.95 | 8.43 | 3.27 |
| 2010 | 4.28 | 6.27 | 3.07 |
| 2009 | 4.01 | 5.53 | 2.19 |
| 2008 | 7.92 | 13.54 | 1.35 |
| 2007 | 6.01 | 9.67 | 1.08 |
| 2006 | 1.39 | 2.24 | 0.83 |
| 2005 | 1.12 | 1.57 | 0.85 |
| 2004 | 1.64 | 2.13 | 1.28 |
| 2003 | 1.94 | 2.51 | 1.58 |