| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.76 | 0.83 | 0.65 |
| 2024 | 0.72 | 0.91 | 0.55 |
| 2023 | 0.81 | 0.96 | 0.69 |
| 2022 | 0.77 | 0.94 | 0.61 |
| 2021 | 1.03 | 1.27 | 0.85 |
| 2020 | 1.19 | 1.43 | 1 |
| 2019 | 1.12 | 1.53 | 0.72 |
| 2018 | 1.36 | 2.53 | 0.76 |
| 2017 | 2.04 | 2.53 | 1.58 |
| 2016 | 2.04 | 2.96 | 1.53 |
| 2015 | 3.03 | 5.05 | 1.69 |
| 2014 | 6.52 | 19.4 | 2.63 |
| 2013 | 5.08 | 7.78 | 3.25 |
| 2012 | 3.14 | 4.09 | 2.42 |
| 2011 | 5.02 | 7.19 | 2.61 |
| 2010 | 4.66 | 8.57 | 3.03 |
| 2009 | 2.26 | 3.31 | 1.26 |
| 2008 | 2.28 | 4.51 | 0.93 |
| 2007 | 4.42 | 7.04 | 2.78 |
| 2006 | 2.6 | 3.39 | 2.01 |
| 2005 | 2.41 | 3.25 | 1.89 |
| 2004 | 3.48 | 4.92 | 2.31 |
| 2003 | 2.51 | 3.15 | 1.83 |
| 2002 | 3.46 | 6.53 | 2.11 |
| 2001 | 7.85 | 9.67 | 5.69 |
| 2000 | 7.23 | 8.86 | 5.44 |
| 1999 | 5.62 | 7.33 | 4.59 |
| 1998 | 8.76 | 14.27 | 4.72 |
| 1997 | 10.06 | 19.35 | 4.11 |