| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.61 | 0.73 | 0.44 |
| 2024 | 0.62 | 0.94 | 0.42 |
| 2023 | 0.8 | 1.01 | 0.64 |
| 2022 | 0.75 | 1.08 | 0.63 |
| 2021 | 0.81 | 1.05 | 0.65 |
| 2020 | 1.22 | 1.57 | 0.81 |
| 2019 | 1.45 | 1.97 | 1.18 |
| 2018 | 1.43 | 2.25 | 0.9 |
| 2017 | 2.03 | 2.3 | 1.49 |
| 2016 | 1.46 | 2.28 | 1.02 |
| 2015 | 1.33 | 1.9 | 0.79 |
| 2014 | 0.92 | 1.31 | 0.68 |
| 2013 | 1.45 | 1.65 | 1.28 |
| 2012 | 1.42 | 1.64 | 1.05 |
| 2011 | 1.76 | 2.43 | 1.1 |
| 2010 | 2.73 | 3.75 | 2.15 |
| 2009 | 2.5 | 4.11 | 1.03 |
| 2008 | 2.33 | 5.31 | 0.83 |
| 2007 | 5.52 | 10.85 | 3.09 |
| 2006 | 2.18 | 3.29 | 1.65 |
| 2005 | 2.32 | 3.4 | 1.84 |
| 2004 | 3.16 | 4.27 | 2.1 |
| 2003 | 2.99 | 4.12 | 2.26 |
| 2002 | 4.97 | 6.09 | 4.3 |
| 2001 | 8.22 | 10.18 | 5.16 |
| 2000 | 10.77 | 18.89 | 6.11 |
| 1999 | 7.96 | 11.99 | 5.64 |
| 1998 | 10.08 | 15.17 | 7.23 |
| 1997 | 6.67 | 11.61 | 4.52 |