| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.99 | 1.13 | 0.8 |
| 2024 | 1 | 1.64 | 0.71 |
| 2023 | 1.44 | 1.64 | 1.24 |
| 2022 | 1.26 | 1.77 | 1 |
| 2021 | 1.53 | 2.04 | 1.29 |
| 2020 | 1.57 | 2.25 | 0.88 |
| 2019 | 1.36 | 1.95 | 0.98 |
| 2018 | 2.38 | 4.42 | 1.15 |
| 2017 | 4.66 | 5.72 | 3.94 |
| 2016 | 4.23 | 6.4 | 3.16 |
| 2015 | 4.32 | 7.33 | 2.59 |
| 2014 | 2.63 | 3.19 | 2.13 |
| 2013 | 2.99 | 3.95 | 2.43 |
| 2012 | 3.11 | 4.1 | 2.25 |
| 2011 | 11.75 | 41.31 | 3.82 |
| 2010 | 14.61 | 21.28 | 9.19 |
| 2009 | 6.87 | 9.65 | 4.34 |
| 2008 | 6.14 | 9.64 | 3.57 |
| 2007 | 6.03 | 8.36 | 3.56 |
| 2006 | 6.49 | 10.13 | 3.29 |
| 2005 | 10.49 | 11.24 | 9.99 |
| 2004 | 12.03 | 14.19 | 10.92 |
| 2003 | 14.73 | 16.23 | 13.38 |
| 2002 | 16.81 | 19.46 | 14.52 |
| 2001 | 17.31 | 21.06 | 14.47 |
| 2000 | 16.05 | 19.66 | 9.6 |
| 1999 | 12.17 | 14.54 | 9.21 |
| 1998 | 6.47 | 8.05 | 4.21 |
| 1997 | 7.28 | 9.75 | 5.55 |