| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.54 | 1.79 | 1.4 |
| 2024 | 1.34 | 2.07 | 1.07 |
| 2023 | 1.66 | 2.24 | 1.51 |
| 2022 | 1.64 | 2.08 | 1.37 |
| 2021 | 1.72 | 2.27 | 1.49 |
| 2020 | 2.36 | 3.39 | 1.95 |
| 2019 | 2.48 | 3.67 | 2.05 |
| 2018 | 3.15 | 4.53 | 2.12 |
| 2017 | 5.05 | 5.83 | 4.53 |
| 2016 | 5.27 | 6.11 | 3.94 |
| 2015 | 5.59 | 11.45 | 3.17 |
| 2014 | 2.14 | 3.17 | 1.67 |
| 2013 | 2.13 | 2.89 | 1.63 |
| 2012 | 3.24 | 4.51 | 1.99 |
| 2011 | 4.58 | 6.37 | 3.32 |
| 2010 | 5.37 | 7.34 | 3.89 |
| 2009 | 4.58 | 6.11 | 3.77 |
| 2008 | 5.13 | 9.19 | 2.76 |
| 2007 | 8.18 | 10.92 | 5.12 |
| 2006 | 4.64 | 5.86 | 3.34 |
| 2005 | 3.64 | 3.9 | 3.41 |
| 2004 | 4.83 | 6.13 | 2.89 |
| 2003 | 5.48 | 6.56 | 4.74 |
| 2002 | 4.84 | 5.65 | 3.28 |
| 2001 | 4.36 | 5.08 | 3.62 |
| 2000 | 3.88 | 5.04 | 2.37 |
| 1999 | 2.57 | 3.6 | 1.87 |
| 1998 | 2.26 | 3 | 1.65 |
| 1997 | 1.81 | 2.67 | 1.34 |