| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 7.78 | 9.12 | 6.6 |
| 2025 | 7.75 | 10.66 | 3.26 |
| 2024 | 2.87 | 4.39 | 2 |
| 2023 | 3.35 | 4.87 | 2.34 |
| 2022 | 2.57 | 4.87 | 1.79 |
| 2021 | 2.01 | 2.24 | 1.77 |
| 2020 | 2.22 | 2.86 | 1.88 |
| 2019 | 2.89 | 4.13 | 1.91 |
| 2018 | 2.13 | 3.29 | 1.7 |
| 2017 | 3.71 | 6.19 | 2.71 |
| 2016 | 4.09 | 5.98 | 2.63 |
| 2015 | 3.57 | 7.1 | 2.31 |
| 2014 | 2.08 | 3 | 1.53 |
| 2013 | 2.19 | 3.63 | 1.46 |
| 2012 | 2.47 | 3.3 | 1.95 |
| 2011 | 4.16 | 5.66 | 2.27 |
| 2010 | 4.75 | 6.33 | 3.7 |
| 2009 | 3.51 | 4.96 | 1.85 |
| 2008 | 3.04 | 5.1 | 1.44 |
| 2007 | 4.87 | 7.4 | 2.58 |
| 2006 | 2.07 | 3.01 | 1.17 |
| 2005 | 1.27 | 1.53 | 0.98 |
| 2004 | 1.72 | 2.51 | 1.28 |
| 2003 | 1.76 | 1.99 | 1.59 |
| 2002 | 2.21 | 2.83 | 1.23 |
| 2001 | 2.91 | 3.64 | 1.94 |
| 2000 | 3.11 | 4.12 | 2.14 |
| 1999 | 2.47 | 3.19 | 1.87 |
| 1998 | 2.95 | 3.68 | 2.09 |