| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.92 | 2.46 | 1.59 |
| 2023 | 1.95 | 2.42 | 1.54 |
| 2022 | 2.03 | 2.58 | 1.69 |
| 2021 | 2.8 | 3.46 | 2.21 |
| 2020 | 3.29 | 4.17 | 2.81 |
| 2019 | 3.45 | 4.51 | 2.48 |
| 2018 | 3.9 | 5.89 | 2.48 |
| 2017 | 3.95 | 5.02 | 2.88 |
| 2016 | 2.58 | 3.7 | 2.1 |
| 2015 | 3.05 | 4.26 | 2.2 |
| 2014 | 2.53 | 3.08 | 2.12 |
| 2013 | 3.03 | 3.62 | 2.49 |
| 2012 | 3.13 | 4.06 | 2.7 |
| 2011 | 4.13 | 5.34 | 2.87 |
| 2010 | 4.4 | 5.98 | 3.22 |
| 2009 | 4.94 | 6.16 | 3.28 |
| 2008 | 6.01 | 12.69 | 2.72 |
| 2007 | 7.36 | 10.29 | 3.19 |
| 2006 | 2.37 | 3.19 | 1.93 |
| 2005 | 2.18 | 2.51 | 1.85 |
| 2004 | 2.67 | 3 | 2.23 |
| 2003 | 2.33 | 2.68 | 2 |
| 2002 | 2.83 | 3.49 | 2.56 |
| 2001 | 3.65 | 4.32 | 2.72 |
| 2000 | 4.98 | 5.66 | 4.35 |
| 1999 | 5.37 | 8.53 | 4.06 |
| 1998 | 7.46 | 12.63 | 3 |
| 1997 | 9.2 | 13.48 | 6.84 |