| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.65 | 2.02 | 1.43 |
| 2024 | 1.66 | 1.99 | 1.2 |
| 2023 | 4.27 | 7.76 | 1.73 |
| 2022 | 3.04 | 3.99 | 2.19 |
| 2021 | 2.53 | 3.85 | 1.87 |
| 2020 | 2.1 | 3.24 | 1.16 |
| 2019 | 1.12 | 1.37 | 0.89 |
| 2018 | 1.05 | 1.36 | 0.85 |
| 2017 | 1.74 | 2.23 | 1.27 |
| 2016 | 1.97 | 2.32 | 1.62 |
| 2015 | 2.01 | 3.94 | 1.3 |
| 2014 | 1.26 | 1.55 | 1.05 |
| 2013 | 0.99 | 1.2 | 0.86 |
| 2012 | 1.01 | 1.2 | 0.83 |
| 2011 | 1.5 | 1.78 | 1.06 |
| 2010 | 1.61 | 1.88 | 1.27 |
| 2009 | 1.43 | 1.79 | 0.94 |
| 2008 | 1.91 | 3.3 | 0.71 |
| 2007 | 2.33 | 3.1 | 1.34 |
| 2006 | 1.19 | 1.48 | 0.9 |
| 2005 | 0.94 | 1.16 | 0.8 |
| 2004 | 1.32 | 1.85 | 1.02 |
| 2003 | 1.69 | 2.15 | 1.38 |
| 2002 | 2.43 | 2.74 | 1.95 |
| 2001 | 3.12 | 3.67 | 2.18 |
| 2000 | 3.5 | 5.03 | 2.57 |
| 1999 | 2.9 | 4.61 | 2.12 |
| 1998 | 3.01 | 3.8 | 2.44 |
| 1997 | 3.1 | 4.76 | 2.14 |