| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.37 | 1.47 | 1.33 |
| 2024 | 1.33 | 1.48 | 1.16 |
| 2023 | 1.39 | 1.6 | 1.09 |
| 2022 | 1.22 | 1.39 | 1.1 |
| 2021 | 1.33 | 1.51 | 1.18 |
| 2020 | 1.52 | 1.93 | 1.33 |
| 2019 | 1.89 | 2.15 | 1.69 |
| 2018 | 1.81 | 2.12 | 1.59 |
| 2017 | 2.18 | 2.49 | 1.97 |
| 2016 | 2.03 | 2.22 | 1.74 |
| 2015 | 2.6 | 4.27 | 1.74 |
| 2014 | 1.9 | 3.19 | 1.54 |
| 2013 | 1.78 | 1.99 | 1.49 |
| 2012 | 1.95 | 2.24 | 1.65 |
| 2011 | 2.62 | 3.28 | 1.97 |
| 2010 | 3.8 | 4.83 | 2.89 |
| 2009 | 4.13 | 4.58 | 3.42 |
| 2008 | 4.61 | 7.49 | 2.91 |
| 2007 | 4.05 | 5.58 | 2.1 |
| 2006 | 2.13 | 2.83 | 1.67 |
| 2005 | 1.83 | 2.09 | 1.47 |
| 2004 | 1.94 | 2.66 | 1.61 |
| 2003 | 2 | 2.53 | 1.67 |
| 2002 | 2.79 | 3.23 | 2.12 |
| 2001 | 3.44 | 4.25 | 2.74 |
| 2000 | 3.02 | 3.65 | 2.27 |
| 1999 | 2.55 | 3.2 | 2.2 |
| 1998 | 3.15 | 4.2 | 2.21 |
| 1997 | 8.67 | 13.36 | 4.11 |