| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.82 | 1.01 | 0.76 |
| 2024 | 0.75 | 0.92 | 0.6 |
| 2023 | 0.83 | 0.94 | 0.74 |
| 2022 | 1.09 | 1.45 | 0.81 |
| 2021 | 1.58 | 2.6 | 1.19 |
| 2020 | 1.35 | 2.23 | 0.89 |
| 2019 | 1.07 | 1.67 | 0.91 |
| 2018 | 1.4 | 1.87 | 0.95 |
| 2017 | 2.22 | 2.72 | 1.66 |
| 2016 | 3.23 | 5.84 | 1.82 |
| 2015 | 3.26 | 4.48 | 1.84 |
| 2014 | 1.81 | 2.11 | 1.46 |
| 2013 | 1.8 | 2.25 | 1.52 |
| 2012 | 1.85 | 2.37 | 1.43 |
| 2011 | 3.05 | 4 | 2.04 |
| 2010 | 3.22 | 3.81 | 2.59 |
| 2009 | 2.16 | 3.06 | 1.35 |
| 2008 | 3.03 | 6.45 | 1.06 |
| 2007 | 4.75 | 7.01 | 2.49 |
| 2006 | 2.07 | 2.69 | 1.43 |
| 2005 | 1.4 | 1.82 | 1.08 |
| 2004 | 1.53 | 1.79 | 1.33 |
| 2003 | 1.56 | 1.78 | 1.32 |
| 2002 | 1.97 | 2.65 | 1.43 |
| 2001 | 3.03 | 3.51 | 2.28 |
| 2000 | 3.02 | 3.58 | 2.11 |
| 1999 | 4.4 | 9.37 | 2.01 |
| 1998 | 7.26 | 9 | 4.69 |