| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.26 | 1.38 | 1.15 |
| 2024 | 1.16 | 1.56 | 0.91 |
| 2023 | 1.38 | 1.54 | 1.2 |
| 2022 | 1.25 | 1.9 | 1.01 |
| 2021 | 1.07 | 1.16 | 0.99 |
| 2020 | 1.17 | 1.61 | 1.04 |
| 2019 | 1.35 | 1.7 | 1.16 |
| 2018 | 1.55 | 2.14 | 1.15 |
| 2017 | 2.51 | 3.54 | 1.85 |
| 2016 | 2.72 | 3.68 | 2.3 |
| 2015 | 3.62 | 6.96 | 2.41 |
| 2014 | 1.83 | 2.86 | 1.47 |
| 2013 | 1.61 | 2.62 | 1.16 |
| 2012 | 1.5 | 1.83 | 1.23 |
| 2011 | 2.04 | 2.74 | 1.3 |
| 2010 | 2.94 | 4.31 | 2.18 |
| 2009 | 3.04 | 4.68 | 1.37 |
| 2008 | 2.78 | 6.3 | 1.06 |
| 2007 | 5.93 | 8.72 | 2.8 |
| 2006 | 1.72 | 2.83 | 0.73 |
| 2005 | 0.84 | 1.15 | 0.61 |
| 2004 | 1.51 | 2.11 | 1.03 |
| 2003 | 1.91 | 2.13 | 1.65 |
| 2002 | 4.26 | 6.68 | 2.8 |
| 2001 | 7.13 | 8.52 | 5.95 |
| 2000 | 7.23 | 8.65 | 6.26 |
| 1999 | 7.31 | 11.8 | 5.05 |
| 1998 | 8.49 | 10.71 | 6.19 |
| 1997 | 3.85 | 5.15 | 2.85 |