| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.67 | 2.54 | 0.76 |
| 2024 | 0.74 | 1.01 | 0.56 |
| 2023 | 0.78 | 0.98 | 0.65 |
| 2022 | 0.8 | 1.03 | 0.65 |
| 2021 | 0.92 | 1.13 | 0.8 |
| 2020 | 1.23 | 1.91 | 0.77 |
| 2019 | 0.85 | 1.07 | 0.71 |
| 2018 | 0.96 | 1.2 | 0.82 |
| 2017 | 1.32 | 1.65 | 1.08 |
| 2016 | 1.96 | 6.5 | 1.08 |
| 2015 | 2.24 | 4.04 | 1.55 |
| 2014 | 1.06 | 1.59 | 0.81 |
| 2013 | 0.91 | 1.18 | 0.72 |
| 2012 | 0.82 | 1 | 0.7 |
| 2011 | 1.18 | 1.59 | 0.89 |
| 2010 | 1.35 | 1.7 | 1.09 |
| 2009 | 1.43 | 2.05 | 0.91 |
| 2008 | 1.46 | 2.54 | 0.7 |
| 2007 | 1.69 | 2.71 | 0.87 |
| 2006 | 0.74 | 0.86 | 0.63 |
| 2005 | 1.05 | 1.52 | 0.74 |
| 2004 | 1.85 | 3.21 | 1.39 |
| 2003 | 2.55 | 3.12 | 2.23 |
| 2002 | 2.78 | 3.08 | 2.39 |
| 2001 | 4.11 | 4.91 | 3.01 |
| 2000 | 5.29 | 6.69 | 3.43 |
| 1999 | 3.45 | 4.13 | 2.79 |