| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.21 | 1.29 | 1.14 |
| 2024 | 1.31 | 1.56 | 1.03 |
| 2023 | 1.56 | 2.07 | 1.13 |
| 2022 | 1.68 | 2.32 | 1.07 |
| 2021 | 1.41 | 2.17 | 1.02 |
| 2020 | 1.02 | 1.23 | 0.82 |
| 2019 | 1.07 | 1.7 | 0.87 |
| 2018 | 0.97 | 1.25 | 0.74 |
| 2017 | 1.13 | 1.27 | 0.99 |
| 2016 | 1.06 | 1.32 | 0.96 |
| 2015 | 2.04 | 3.45 | 1.18 |
| 2014 | 1.47 | 2.14 | 1.24 |
| 2013 | 1.53 | 2.02 | 1.21 |
| 2012 | 2.59 | 3.84 | 1.47 |
| 2011 | 4.68 | 7.09 | 3.46 |
| 2010 | 8.07 | 14.96 | 4.25 |
| 2009 | 15.56 | 22.52 | 11.89 |
| 2008 | 17.58 | 27.44 | 9.09 |
| 2007 | 11.81 | 24.32 | 5.4 |
| 2006 | 4.19 | 5.46 | 3.21 |
| 2005 | 2.68 | 3.71 | 1.87 |
| 2004 | 3.27 | 4.5 | 2.5 |
| 2003 | 2.44 | 2.87 | 2.05 |
| 2002 | 2.4 | 2.91 | 1.23 |
| 2001 | 2.5 | 3.28 | 1.86 |
| 2000 | 2.09 | 2.63 | 1.56 |
| 1999 | 1.41 | 1.77 | 1.08 |
| 1998 | 1.43 | 1.93 | 1.23 |
| 1997 | 1.62 | 2.15 | 1.19 |