| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.94 | 2.16 | 1.7 |
| 2024 | 1.72 | 2.72 | 1.19 |
| 2023 | 1.38 | 1.62 | 1.21 |
| 2022 | 1.24 | 1.67 | 1.03 |
| 2021 | 1.06 | 1.21 | 0.92 |
| 2020 | 1.28 | 1.69 | 1 |
| 2019 | 1.29 | 1.72 | 1 |
| 2018 | 1.32 | 2.13 | 0.89 |
| 2017 | 2.28 | 2.92 | 1.87 |
| 2016 | 2.36 | 2.9 | 1.92 |
| 2015 | 3.08 | 4.74 | 1.88 |
| 2014 | 2.24 | 3.07 | 1.82 |
| 2013 | 2.26 | 3.31 | 1.5 |
| 2012 | 2.17 | 3.54 | 1.5 |
| 2011 | 3.15 | 4.13 | 1.87 |
| 2010 | 3.91 | 4.95 | 3.18 |
| 2009 | 2.77 | 4.52 | 1.66 |
| 2008 | 6.53 | 21.28 | 1.18 |
| 2007 | 6.84 | 13.96 | 2.21 |
| 2006 | 2.04 | 2.54 | 1.58 |
| 2005 | 2.02 | 2.48 | 1.61 |
| 2004 | 2.9 | 3.78 | 2.3 |
| 2003 | 3.42 | 4.39 | 2.14 |
| 2002 | 5.67 | 7.21 | 4.78 |
| 2001 | 7.33 | 8 | 6.23 |
| 2000 | 6.2 | 6.98 | 5.14 |
| 1999 | 5.01 | 6.14 | 3.96 |
| 1998 | 3.68 | 5.44 | 2.54 |
| 1997 | 3.29 | 5.75 | 2.26 |