| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.68 | 2.1 | 1.42 |
| 2024 | 1.47 | 1.74 | 1.11 |
| 2023 | 1.62 | 1.84 | 1.37 |
| 2022 | 2.16 | 3.06 | 1.66 |
| 2021 | 3.92 | 6.26 | 2.24 |
| 2020 | 3.61 | 13.61 | 2.25 |
| 2019 | 4.22 | 5.8 | 3.54 |
| 2018 | 4.1 | 5.56 | 3.14 |
| 2017 | 7.17 | 9.72 | 4.84 |
| 2016 | 7.68 | 10.51 | 4.89 |
| 2015 | 7.17 | 13.89 | 4.91 |
| 2014 | 5.23 | 6.75 | 4.22 |
| 2013 | 4.13 | 5.19 | 3.18 |
| 2012 | 3.76 | 5.04 | 2.8 |
| 2011 | 5.91 | 8.12 | 3.92 |
| 2010 | 6.71 | 8.37 | 4.93 |
| 2009 | 5.46 | 7.95 | 2.72 |
| 2008 | 5.81 | 12.24 | 1.85 |
| 2007 | 5.71 | 9.53 | 2.46 |
| 2006 | 2.5 | 3.44 | 1.93 |
| 2005 | 2.19 | 3.02 | 1.51 |
| 2004 | 4.19 | 5.92 | 2.7 |
| 2003 | 6.04 | 6.89 | 4.83 |
| 2002 | 8.08 | 10.09 | 6.55 |
| 2001 | 14.95 | 22.99 | 9.38 |
| 2000 | 13.24 | 18.17 | 8.27 |
| 1999 | 7.63 | 10.54 | 5.36 |
| 1998 | 4.99 | 6.93 | 3.45 |
| 1997 | 4.61 | 6.49 | 3.56 |