| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.1 | 2.58 | 1.72 |
| 2024 | 1.42 | 1.81 | 1.07 |
| 2023 | 1.13 | 1.21 | 1.08 |
| 2022 | 1.18 | 1.35 | 1.02 |
| 2021 | 1.48 | 1.69 | 1.3 |
| 2020 | 1.58 | 1.98 | 1.4 |
| 2019 | 2.1 | 2.37 | 1.85 |
| 2018 | 2.16 | 2.67 | 1.8 |
| 2017 | 2.42 | 2.62 | 2.13 |
| 2016 | 2.39 | 2.62 | 2.22 |
| 2015 | 2.46 | 2.91 | 1.77 |
| 2014 | 1.78 | 2.55 | 1.58 |
| 2013 | 2.15 | 2.84 | 1.67 |
| 2012 | 2.19 | 2.87 | 1.73 |
| 2011 | 3.4 | 4.39 | 2.47 |
| 2010 | 4.59 | 5.96 | 3.44 |
| 2009 | 4.72 | 6.51 | 2.4 |
| 2008 | 5.03 | 11.57 | 2.06 |
| 2007 | 8.26 | 11.86 | 5.56 |
| 2006 | 3.38 | 5.69 | 2.45 |
| 2005 | 2.96 | 3.49 | 2.44 |
| 2004 | 4.86 | 7.75 | 3 |
| 2003 | 8.34 | 10.97 | 5.39 |
| 2002 | 11.27 | 13.87 | 8.34 |
| 2001 | 21.51 | 26.92 | 14.3 |
| 2000 | 30.26 | 35.59 | 25.93 |