| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 2.79 | 3.12 | 2.27 |
| 2025 | 2.53 | 3.44 | 1.77 |
| 2024 | 1.81 | 2.54 | 1.26 |
| 2023 | 2.62 | 3.29 | 2.19 |
| 2022 | 3.1 | 4.04 | 2.58 |
| 2021 | 3.04 | 4.44 | 2.26 |
| 2020 | 3.46 | 5.03 | 2.31 |
| 2019 | 3.64 | 4.94 | 2.68 |
| 2018 | 5.36 | 9.51 | 2.08 |
| 2017 | 5.73 | 6.44 | 4.8 |
| 2016 | 5.87 | 8.07 | 4.98 |
| 2015 | 6.84 | 13.16 | 3.86 |
| 2014 | 5.01 | 6.03 | 3.93 |
| 2013 | 11.11 | 22.93 | 3.42 |
| 2012 | 11.41 | 18.33 | 6.55 |
| 2011 | 10.57 | 13.42 | 6.15 |
| 2010 | 6.1 | 7.51 | 4.51 |
| 2009 | 5.05 | 7.39 | 2.48 |
| 2008 | 3.92 | 6.32 | 1.73 |
| 2007 | 3.71 | 5.56 | 1.94 |
| 2006 | 2.03 | 3.27 | 0.94 |
| 2005 | 0.98 | 1.26 | 0.62 |
| 2004 | 1.45 | 1.94 | 1.07 |
| 2003 | 1.78 | 2.13 | 1.41 |
| 2002 | 1.99 | 2.27 | 1.59 |
| 2001 | 2.51 | 3.08 | 1.73 |
| 2000 | 2.25 | 2.7 | 1.57 |
| 1999 | 1.67 | 2.15 | 1.36 |
| 1998 | 2.24 | 2.74 | 1.86 |
| 1997 | 2.95 | 4.35 | 2.15 |