| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.52 | 1.85 | 1.34 |
| 2024 | 1.6 | 2.31 | 1.3 |
| 2023 | 1.78 | 2.1 | 1.45 |
| 2022 | 1.63 | 3.46 | 0.9 |
| 2021 | 1.08 | 1.57 | 0.86 |
| 2020 | 0.92 | 1.61 | 0.84 |
| 2019 | 1.04 | 1.29 | 0.92 |
| 2018 | 0.97 | 1.27 | 0.79 |
| 2017 | 1.63 | 2.02 | 1.19 |
| 2016 | 2.26 | 3.57 | 1.57 |
| 2015 | 3.15 | 5.55 | 2.21 |
| 2014 | 1.88 | 2.36 | 1.59 |
| 2013 | 2.33 | 3.28 | 1.92 |
| 2012 | 2.09 | 2.44 | 1.79 |
| 2011 | 3 | 4.03 | 2.06 |
| 2010 | 2.89 | 3.51 | 2.01 |
| 2009 | 2.76 | 3.95 | 1.72 |
| 2008 | 2.24 | 4.35 | 1.03 |
| 2007 | 2.9 | 4.79 | 1.24 |
| 2006 | 1.13 | 1.4 | 0.86 |
| 2005 | 1.16 | 1.59 | 0.93 |
| 2004 | 3 | 5.59 | 1.54 |
| 2003 | 2.2 | 2.56 | 1.97 |
| 2002 | 2.57 | 3.05 | 1.81 |
| 2001 | 3.45 | 4.19 | 2.58 |
| 2000 | 5.11 | 6.49 | 3.77 |
| 1999 | 4.72 | 8.05 | 3.4 |
| 1998 | 4.78 | 6.06 | 3.02 |