| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.55 | 1.98 | 1.05 |
| 2023 | 1.51 | 1.82 | 1.1 |
| 2022 | 1.01 | 1.3 | 0.79 |
| 2021 | 1.08 | 1.45 | 0.89 |
| 2020 | 1.11 | 1.35 | 0.86 |
| 2019 | 0.85 | 1.18 | 0.69 |
| 2018 | 1.19 | 1.67 | 0.76 |
| 2017 | 1.56 | 2 | 1.31 |
| 2016 | 1.79 | 2.13 | 1.49 |
| 2015 | 2.42 | 4.26 | 1.49 |
| 2014 | 1.44 | 1.75 | 1.19 |
| 2013 | 1.77 | 2.36 | 1.44 |
| 2012 | 1.84 | 2.93 | 1.28 |
| 2011 | 1.94 | 2.54 | 1.44 |
| 2010 | 2.84 | 4.92 | 1.86 |
| 2009 | 2.2 | 4.69 | 1.14 |
| 2008 | 1.51 | 2.7 | 0.88 |
| 2007 | 2 | 2.62 | 1.24 |
| 2006 | 1.34 | 1.75 | 1.12 |
| 2005 | 1.18 | 1.36 | 0.9 |
| 2004 | 1.54 | 1.89 | 1.15 |
| 2003 | 1.62 | 1.88 | 1.27 |
| 2002 | 2.22 | 3.31 | 1.69 |
| 2001 | 4.13 | 5.12 | 3.13 |
| 2000 | 4.49 | 5.25 | 3.61 |
| 1999 | 3.98 | 5.45 | 3.08 |
| 1998 | 6.09 | 8.42 | 4.75 |