| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 2.61 | 2.76 | 2.36 |
| 2025 | 2.67 | 3.15 | 2.41 |
| 2024 | 2.39 | 3.08 | 1.69 |
| 2023 | 2.16 | 2.91 | 1.77 |
| 2022 | 1.64 | 2.17 | 1.33 |
| 2021 | 1.35 | 1.57 | 1.24 |
| 2020 | 1.31 | 1.48 | 1.18 |
| 2019 | 1.4 | 1.74 | 1.21 |
| 2018 | 1.94 | 2.76 | 1.27 |
| 2017 | 2.99 | 3.59 | 2.31 |
| 2016 | 3.44 | 3.94 | 3.13 |
| 2015 | 3.78 | 5.56 | 2.69 |
| 2014 | 3.3 | 4.51 | 2.83 |
| 2013 | 4.23 | 5.6 | 3.09 |
| 2012 | 5.09 | 6.14 | 4.12 |
| 2011 | 5.44 | 6.44 | 4.58 |
| 2010 | 5.87 | 7.52 | 4.36 |
| 2009 | 3.59 | 4.76 | 2.24 |
| 2008 | 3.63 | 6.81 | 1.85 |
| 2007 | 5.56 | 7.65 | 3.68 |
| 2006 | 2.84 | 3.9 | 2.21 |
| 2005 | 2.31 | 4.92 | 1.76 |
| 2004 | 2.7 | 3.22 | 2.42 |
| 2003 | 2.66 | 3.22 | 2.06 |
| 2002 | 3.63 | 4.07 | 2.76 |
| 2001 | 4.51 | 5.47 | 3.09 |
| 2000 | 4.65 | 5.43 | 3.72 |
| 1999 | 3.77 | 5.06 | 3.14 |
| 1998 | 3.71 | 4.55 | 2.68 |