| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.07 | 1.23 | 1 |
| 2024 | 0.9 | 1.17 | 0.76 |
| 2023 | 1.1 | 1.25 | 0.9 |
| 2022 | 1.24 | 1.38 | 1.12 |
| 2021 | 1.42 | 1.64 | 1.27 |
| 2020 | 1.61 | 1.89 | 1.47 |
| 2019 | 1.94 | 2.81 | 1.42 |
| 2018 | 1.91 | 2.19 | 1.38 |
| 2017 | 2.22 | 2.59 | 1.96 |
| 2016 | 2.49 | 3.13 | 2.07 |
| 2015 | 4.05 | 5.91 | 2.32 |
| 2014 | 5.28 | 6.99 | 3.79 |
| 2013 | 4.27 | 12.24 | 1.97 |
| 2012 | 1.86 | 2.36 | 1.43 |
| 2011 | 2.9 | 3.95 | 1.99 |
| 2010 | 3.41 | 4.38 | 2.56 |
| 2009 | 5.04 | 8.09 | 3.49 |
| 2008 | 5.77 | 11.69 | 2.08 |
| 2007 | 8.47 | 12.38 | 4.22 |
| 2006 | 3.56 | 4.73 | 2.61 |
| 2005 | 2.65 | 3.42 | 1.69 |
| 2004 | 3.88 | 5.49 | 2.93 |
| 2003 | 4.78 | 5.78 | 3.88 |
| 2002 | 6.05 | 6.8 | 4.98 |
| 2001 | 7.11 | 9.53 | 5.32 |
| 2000 | 6.66 | 9.04 | 5.63 |
| 1999 | 5.41 | 7.76 | 3.98 |
| 1998 | 10.45 | 13.61 | 7.92 |
| 1997 | 14.73 | 20.94 | 11.78 |