| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.07 | 1.94 | 0.89 |
| 2024 | 0.93 | 1.17 | 0.76 |
| 2023 | 1.21 | 1.33 | 1.07 |
| 2022 | 1.33 | 1.75 | 1.11 |
| 2021 | 1.47 | 1.81 | 1.3 |
| 2020 | 1.36 | 1.78 | 1.1 |
| 2019 | 1.49 | 2.02 | 1.21 |
| 2018 | 2.04 | 3.26 | 1.39 |
| 2017 | 3.53 | 4.54 | 2.94 |
| 2016 | 2.81 | 3.4 | 2.14 |
| 2015 | 3.64 | 5.47 | 2.39 |
| 2014 | 3.46 | 4.73 | 2.96 |
| 2013 | 3.42 | 4.34 | 2.9 |
| 2012 | 2.92 | 3.68 | 1.87 |
| 2011 | 3.13 | 4.17 | 1.95 |
| 2010 | 3.84 | 4.89 | 2.74 |
| 2009 | 4.66 | 6.63 | 2.63 |
| 2008 | 4.79 | 8.44 | 2.12 |
| 2007 | 6.18 | 10.03 | 2.12 |
| 2006 | 1.82 | 2.51 | 1.22 |
| 2005 | 1.35 | 1.7 | 1.09 |
| 2004 | 2.26 | 3.09 | 1.62 |
| 2003 | 2.8 | 3.42 | 2.27 |
| 2002 | 3.74 | 4.13 | 2.88 |
| 2001 | 4.68 | 5.65 | 3.34 |
| 2000 | 7.67 | 12.28 | 5.18 |
| 1999 | 5.43 | 7.26 | 3.96 |
| 1998 | 5.28 | 7.01 | 3.79 |
| 1997 | 6.47 | 9.54 | 5.28 |