| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.82 | 2.5 | 1.26 |
| 2024 | 1.31 | 1.56 | 0.98 |
| 2023 | 1.53 | 2.01 | 1.31 |
| 2022 | 2.15 | 3.31 | 1.49 |
| 2021 | 1.84 | 3.07 | 1.3 |
| 2020 | 1.43 | 1.94 | 1.03 |
| 2019 | 1.42 | 1.95 | 1.09 |
| 2018 | 2.23 | 3.19 | 1.36 |
| 2017 | 3.92 | 5.24 | 2.82 |
| 2016 | 6.09 | 8.35 | 4.49 |
| 2015 | 8.7 | 14.53 | 5.72 |
| 2014 | 4.92 | 7.65 | 3.71 |
| 2013 | 3.95 | 4.71 | 3.19 |
| 2012 | 3.91 | 5.68 | 2.8 |
| 2011 | 7.07 | 11.59 | 4.61 |
| 2010 | 8.07 | 10.41 | 6.5 |
| 2009 | 6.74 | 8.6 | 3.97 |
| 2008 | 8.62 | 15.95 | 3.23 |
| 2007 | 10.53 | 13.98 | 6.11 |
| 2006 | 3.73 | 7.64 | 1.52 |
| 2005 | 1.11 | 1.47 | 0.74 |
| 2004 | 1.67 | 2.26 | 1.16 |
| 2003 | 2.29 | 2.9 | 1.72 |
| 2002 | 3.61 | 5.15 | 2.84 |
| 2001 | 6.9 | 8.7 | 4.55 |
| 2000 | 7.3 | 8.64 | 5.97 |
| 1999 | 6.2 | 8.7 | 3.9 |