| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.59 | 0.8 | 0.55 |
| 2024 | 0.62 | 0.85 | 0.47 |
| 2023 | 0.84 | 0.98 | 0.74 |
| 2022 | 1.07 | 1.48 | 0.74 |
| 2021 | 0.93 | 1.14 | 0.79 |
| 2020 | 1.05 | 1.22 | 0.86 |
| 2019 | 1.42 | 2.16 | 1.11 |
| 2018 | 1.83 | 2.44 | 1.28 |
| 2017 | 2.83 | 3.35 | 2.08 |
| 2016 | 3.75 | 5.33 | 3.13 |
| 2015 | 9.21 | 18.37 | 4.16 |
| 2014 | 5.77 | 8.4 | 4.54 |
| 2013 | 5.86 | 7.7 | 4.03 |
| 2012 | 15.65 | 47.14 | 4.58 |
| 2011 | 14.15 | 21.43 | 11.01 |
| 2010 | 8.48 | 13.32 | 4.74 |
| 2009 | 4.79 | 7.04 | 1.89 |
| 2008 | 3.72 | 6.8 | 1.92 |
| 2007 | 2.87 | 4.84 | 1.22 |
| 2006 | 1.11 | 1.36 | 0.86 |
| 2005 | 1.17 | 1.65 | 0.82 |
| 2004 | 2.48 | 3.77 | 1.69 |
| 2003 | 3.37 | 3.83 | 3.01 |
| 2002 | 4.71 | 5.63 | 3.75 |
| 2001 | 5.34 | 6.09 | 4.65 |
| 2000 | 9.33 | 12.17 | 7.12 |
| 1999 | 7.65 | 12.62 | 5.56 |