| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.28 | 2.45 | 2.18 |
| 2024 | 2.46 | 2.77 | 2.25 |
| 2023 | 2.42 | 2.67 | 2.14 |
| 2022 | 2.49 | 3.23 | 2.11 |
| 2021 | 3.16 | 4.06 | 2.56 |
| 2020 | 3.68 | 4.9 | 2.88 |
| 2019 | 2.28 | 2.9 | 1.58 |
| 2018 | 2.98 | 4.11 | 1.69 |
| 2017 | 3.9 | 5.23 | 3.23 |
| 2016 | 4.15 | 5.29 | 3.54 |
| 2015 | 4.97 | 7.26 | 3.92 |
| 2014 | 4.15 | 5.02 | 3.59 |
| 2013 | 3.83 | 5.05 | 3.2 |
| 2012 | 2.69 | 3.73 | 1.99 |
| 2011 | 3.34 | 5.17 | 2.11 |
| 2010 | 5.68 | 7.72 | 4.63 |
| 2009 | 4.65 | 7.53 | 3 |
| 2008 | 3.57 | 7.24 | 1.79 |
| 2007 | 4.56 | 7.73 | 1.43 |
| 2006 | 1.48 | 1.75 | 1.2 |
| 2005 | 1.05 | 1.33 | 0.72 |
| 2004 | 1.38 | 2.06 | 1.05 |
| 2003 | 1.87 | 2.36 | 1.33 |
| 2002 | 2.24 | 2.54 | 1.5 |
| 2001 | 2.7 | 3.43 | 1.77 |
| 2000 | 2.3 | 3.21 | 1.52 |
| 1999 | 1.5 | 1.95 | 1.09 |
| 1998 | 1.63 | 2.2 | 1.34 |
| 1997 | 2.18 | 3.66 | 1.46 |