| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.89 | 1.03 | 0.71 |
| 2023 | 1.06 | 1.21 | 0.9 |
| 2022 | 1.34 | 1.98 | 1 |
| 2021 | 1.58 | 2.05 | 1.13 |
| 2020 | 1.61 | 2.22 | 1.18 |
| 2019 | 1.53 | 1.79 | 1.24 |
| 2018 | 1.69 | 2.28 | 1.21 |
| 2017 | 1.73 | 2.37 | 1.35 |
| 2016 | 1.48 | 1.89 | 1.21 |
| 2015 | 1.96 | 2.64 | 1.24 |
| 2014 | 1.45 | 2.01 | 1.05 |
| 2013 | 1.24 | 1.56 | 0.92 |
| 2012 | 1.44 | 1.76 | 1.21 |
| 2011 | 1.89 | 2.53 | 1.33 |
| 2010 | 2.12 | 3.06 | 1.52 |
| 2009 | 2.66 | 7.02 | 1.63 |
| 2008 | 2.42 | 3.42 | 1.27 |
| 2007 | 3.33 | 5.54 | 1.82 |
| 2006 | 1.49 | 1.85 | 1.15 |
| 2005 | 1.52 | 1.91 | 1.21 |
| 2004 | 2.37 | 3.67 | 1.8 |
| 2003 | 3.48 | 4.42 | 2.79 |
| 2002 | 4.01 | 4.76 | 3.54 |
| 2001 | 4.6 | 5.25 | 3.63 |
| 2000 | 6.89 | 7.95 | 5.81 |
| 1999 | 6.07 | 8.72 | 4.77 |
| 1998 | 15.67 | 32.31 | 7.08 |
| 1997 | 8.61 | 10.31 | 5.11 |