| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.67 | 1.88 | 1.46 |
| 2025 | 1.68 | 2.21 | 1.37 |
| 2024 | 1.06 | 1.56 | 0.78 |
| 2023 | 1.45 | 1.71 | 1.22 |
| 2022 | 1.4 | 2.14 | 1.1 |
| 2021 | 1.13 | 1.4 | 0.9 |
| 2020 | 1.08 | 1.42 | 0.94 |
| 2019 | 1.22 | 1.52 | 1.04 |
| 2018 | 1.5 | 2.05 | 1.1 |
| 2017 | 2.62 | 4.33 | 1.72 |
| 2016 | 3.39 | 4.72 | 2.44 |
| 2015 | 2.61 | 4.71 | 1.67 |
| 2014 | 1.71 | 2.1 | 1.33 |
| 2013 | 1.94 | 2.43 | 1.7 |
| 2012 | 1.79 | 2.07 | 1.5 |
| 2011 | 2.03 | 2.4 | 1.64 |
| 2010 | 2.09 | 2.53 | 1.72 |
| 2009 | 1.86 | 2.69 | 0.93 |
| 2008 | 1.69 | 3.08 | 0.73 |
| 2007 | 2.66 | 4.11 | 1.22 |
| 2006 | 1.04 | 1.3 | 0.73 |
| 2005 | 0.8 | 1.04 | 0.59 |
| 2004 | 1.26 | 1.61 | 0.93 |
| 2003 | 1.46 | 1.88 | 1.29 |
| 2002 | 1.83 | 2.23 | 1.15 |
| 2001 | 2.2 | 2.66 | 1.62 |
| 2000 | 2.43 | 3.04 | 1.67 |
| 1999 | 1.7 | 2.43 | 1.36 |
| 1998 | 2.3 | 2.76 | 1.7 |
| 1997 | 3.15 | 4.77 | 2.43 |