| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.64 | 1.83 | 1.48 |
| 2024 | 1.45 | 1.98 | 1.16 |
| 2023 | 1.77 | 2.19 | 1.45 |
| 2022 | 1.91 | 2.21 | 1.6 |
| 2021 | 2.16 | 2.63 | 1.8 |
| 2020 | 2.9 | 3.52 | 2.47 |
| 2019 | 3.08 | 4.02 | 2.38 |
| 2018 | 3.15 | 5.18 | 2.1 |
| 2017 | 2.31 | 2.86 | 1.95 |
| 2016 | 2.68 | 4.92 | 2.14 |
| 2015 | 4.22 | 6.57 | 2.7 |
| 2014 | 3.5 | 4.6 | 2.86 |
| 2013 | 3.33 | 4.59 | 2.65 |
| 2012 | 2.66 | 3.36 | 2.16 |
| 2011 | 3.58 | 4.67 | 2.11 |
| 2010 | 4.75 | 7.33 | 3.61 |
| 2009 | 2.75 | 3.84 | 1.8 |
| 2008 | 3.14 | 5.5 | 1.59 |
| 2007 | 4.01 | 6.46 | 1.48 |
| 2006 | 1.31 | 1.65 | 0.86 |
| 2005 | 1.03 | 1.42 | 0.77 |
| 2004 | 1.75 | 2.39 | 1.27 |
| 2003 | 2.01 | 2.43 | 1.77 |
| 2002 | 3.46 | 5.82 | 2.54 |
| 2001 | 5.11 | 6.16 | 3.47 |
| 2000 | 5.84 | 8.57 | 3.11 |
| 1999 | 4.12 | 6.91 | 3.04 |
| 1998 | 4.07 | 4.7 | 3.06 |