| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.15 | 1.29 | 1.12 |
| 2024 | 1.23 | 1.35 | 1.11 |
| 2023 | 1.48 | 1.71 | 1.28 |
| 2022 | 1.78 | 2.26 | 1.37 |
| 2021 | 1.71 | 2.16 | 1.46 |
| 2020 | 3.14 | 6.84 | 1.56 |
| 2019 | 2.81 | 3.71 | 2.28 |
| 2018 | 2.8 | 3.52 | 2.22 |
| 2017 | 4.05 | 5.54 | 3.09 |
| 2016 | 3.67 | 5.46 | 2.55 |
| 2015 | 3.19 | 6.44 | 1.78 |
| 2014 | 2.48 | 3.36 | 2.19 |
| 2013 | 2.74 | 3.45 | 2.21 |
| 2012 | 3.33 | 4.25 | 2.65 |
| 2011 | 4.44 | 6.62 | 3.1 |
| 2010 | 3.34 | 4.09 | 2.32 |
| 2009 | 3.07 | 3.92 | 2.06 |
| 2008 | 3.29 | 5.94 | 1.64 |
| 2007 | 4.45 | 6.77 | 1.76 |
| 2006 | 2.16 | 2.71 | 1.76 |
| 2005 | 1.75 | 2.21 | 1.41 |
| 2004 | 2.5 | 3.04 | 2.07 |
| 2003 | 2.93 | 3.96 | 2.22 |
| 2002 | 4.26 | 4.75 | 3.22 |
| 2001 | 5.04 | 6.02 | 3.73 |
| 2000 | 4.19 | 5.55 | 3.32 |
| 1999 | 3.62 | 4.67 | 2.99 |
| 1998 | 3.81 | 4.87 | 2.95 |