| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.08 | 1.12 | 1 |
| 2024 | 1.18 | 1.3 | 1.03 |
| 2023 | 1.43 | 1.79 | 1.14 |
| 2022 | 1.88 | 2.66 | 1.46 |
| 2021 | 2.57 | 3.64 | 1.76 |
| 2020 | 1.76 | 2.45 | 1.32 |
| 2019 | 1.49 | 1.91 | 1.27 |
| 2018 | 1.84 | 2.74 | 1.26 |
| 2017 | 2.64 | 3.23 | 2.25 |
| 2016 | 2.99 | 3.99 | 2.48 |
| 2015 | 2.96 | 4.39 | 2.06 |
| 2014 | 2.02 | 2.46 | 1.69 |
| 2013 | 2.65 | 3.59 | 2.12 |
| 2012 | 2.62 | 3.49 | 1.96 |
| 2011 | 5.23 | 8.06 | 2.67 |
| 2010 | 5.37 | 8.35 | 3.28 |
| 2009 | 4.13 | 5.72 | 2.28 |
| 2008 | 5.05 | 11.75 | 1.56 |
| 2007 | 7.27 | 13.46 | 4.35 |
| 2006 | 3.05 | 4.4 | 1.98 |
| 2005 | 1.29 | 2.13 | 0.75 |
| 2004 | 1.73 | 2.15 | 1.45 |
| 2003 | 1.9 | 2.54 | 1.31 |
| 2002 | 2.88 | 4.17 | 1.76 |
| 2001 | 4.46 | 6.53 | 2.51 |
| 2000 | 5.11 | 7.18 | 1.35 |
| 1999 | 1.52 | 2.02 | 1.2 |
| 1998 | 1.74 | 2.44 | 1.36 |
| 1997 | 2.77 | 4.22 | 1.7 |