| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.9 | 2.11 | 1.78 |
| 2024 | 1.94 | 2.49 | 1.49 |
| 2023 | 2.6 | 3.13 | 2.15 |
| 2022 | 2.21 | 3.12 | 1.73 |
| 2021 | 3.68 | 5.58 | 2.5 |
| 2020 | 3.61 | 5.64 | 1.72 |
| 2019 | 1.28 | 1.86 | 0.87 |
| 2018 | 1.39 | 2.05 | 0.95 |
| 2017 | 2.37 | 2.77 | 1.94 |
| 2016 | 2.86 | 3.48 | 2.45 |
| 2015 | 3.41 | 4.91 | 2.25 |
| 2014 | 3.25 | 3.71 | 2.84 |
| 2013 | 4.26 | 5.52 | 3.13 |
| 2012 | 3.73 | 4.27 | 3.18 |
| 2011 | 5.1 | 6.46 | 3.7 |
| 2010 | 4.88 | 7.28 | 3.63 |
| 2009 | 3.34 | 5.24 | 1.79 |
| 2008 | 2.31 | 4.12 | 1.18 |
| 2007 | 3.22 | 4.87 | 1.44 |
| 2006 | 1.51 | 2.35 | 1.1 |
| 2005 | 1.29 | 1.69 | 1.02 |
| 2004 | 2.24 | 3.74 | 1.62 |
| 2003 | 3.96 | 5.83 | 2.7 |
| 2002 | 5.62 | 6.32 | 4.53 |
| 2001 | 8.69 | 10.55 | 5.66 |
| 2000 | 8.29 | 11.83 | 4.48 |
| 1999 | 5.73 | 8.04 | 4.7 |
| 1998 | 5.6 | 7.15 | 4.31 |