| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.21 | 1.4 | 1 |
| 2024 | 1.23 | 1.57 | 0.92 |
| 2023 | 1.65 | 2.59 | 1.08 |
| 2022 | 1.21 | 1.65 | 0.97 |
| 2021 | 1.04 | 1.54 | 0.9 |
| 2020 | 1.21 | 1.47 | 1.02 |
| 2019 | 1.67 | 2.67 | 1.31 |
| 2018 | 1.93 | 2.76 | 1.4 |
| 2017 | 4.84 | 9.28 | 2.59 |
| 2016 | 4.6 | 6.68 | 3.38 |
| 2015 | 6.61 | 15.38 | 3.45 |
| 2014 | 4.59 | 6.08 | 3.46 |
| 2013 | 3.23 | 4.31 | 2.33 |
| 2012 | 3.57 | 4.77 | 2.37 |
| 2011 | 6.23 | 8.38 | 3.96 |
| 2010 | 9.69 | 13.7 | 6.83 |
| 2009 | 8.64 | 11.19 | 2.74 |
| 2008 | 3.82 | 7.79 | 2 |
| 2007 | 4.88 | 7.96 | 1.66 |
| 2006 | 1.85 | 2.39 | 1.54 |
| 2005 | 1.98 | 2.61 | 1.44 |
| 2004 | 3.08 | 4.5 | 2.15 |
| 2003 | 3.87 | 4.84 | 3.6 |
| 2002 | 5.19 | 5.95 | 4.32 |
| 2001 | 10.22 | 18.5 | 4.51 |
| 2000 | 10.53 | 13.63 | 8 |
| 1999 | 8.45 | 11.26 | 4.91 |