| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.27 | 1.37 | 1.18 |
| 2024 | 1.27 | 1.47 | 1.08 |
| 2023 | 1.29 | 1.63 | 1.04 |
| 2022 | 1.2 | 1.48 | 0.97 |
| 2021 | 1.41 | 1.96 | 1.21 |
| 2020 | 1.34 | 1.63 | 1.11 |
| 2019 | 1.54 | 2.1 | 1.28 |
| 2018 | 1.92 | 2.89 | 1.37 |
| 2017 | 3.09 | 3.97 | 2.43 |
| 2016 | 3.3 | 4.07 | 2.62 |
| 2015 | 4.44 | 8.81 | 2.8 |
| 2014 | 2.37 | 3.35 | 1.82 |
| 2013 | 2.94 | 4.33 | 2.31 |
| 2012 | 3.36 | 4.25 | 2.73 |
| 2011 | 5.66 | 8.45 | 3.16 |
| 2010 | 6.59 | 9.54 | 4.63 |
| 2009 | 5.71 | 9.01 | 2.21 |
| 2008 | 4.53 | 9.89 | 1.62 |
| 2007 | 8.19 | 14.88 | 5.01 |
| 2006 | 4.35 | 7.29 | 2.09 |
| 2005 | 2.24 | 2.67 | 1.87 |
| 2004 | 2.7 | 3.71 | 2.09 |
| 2003 | 2.48 | 3.27 | 2.05 |
| 2002 | 2.98 | 3.82 | 2.05 |
| 2001 | 3.79 | 4.58 | 2.64 |
| 2000 | 3.87 | 4.51 | 2.78 |
| 1999 | 4.26 | 10.7 | 2.37 |
| 1998 | 3.7 | 4.95 | 2.7 |