| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.97 | 2.6 | 1.56 |
| 2023 | 2.11 | 3.03 | 1.66 |
| 2022 | 2.08 | 3.31 | 1.24 |
| 2021 | 2.32 | 3.14 | 1.61 |
| 2020 | 1.41 | 3.13 | 0.98 |
| 2019 | 0.85 | 1.11 | 0.68 |
| 2018 | 0.92 | 1.38 | 0.58 |
| 2017 | 1.59 | 2.02 | 1.29 |
| 2016 | 2.02 | 2.48 | 1.7 |
| 2015 | 3.22 | 4.7 | 1.89 |
| 2014 | 2.88 | 3.58 | 2.37 |
| 2013 | 2.9 | 3.42 | 1.99 |
| 2012 | 1.6 | 2.09 | 1.25 |
| 2011 | 1.79 | 2.72 | 1.1 |
| 2010 | 2.81 | 4.08 | 2.09 |
| 2009 | 2.77 | 4.31 | 1.08 |
| 2008 | 2.09 | 5.3 | 1.04 |
| 2007 | 4 | 6.09 | 2.16 |
| 2006 | 1.28 | 2.02 | 0.91 |
| 2005 | 0.94 | 1.25 | 0.71 |
| 2004 | 2.37 | 5.12 | 1.02 |
| 2003 | 4.88 | 6.72 | 3.77 |
| 2002 | 2.58 | 3.12 | 1.85 |
| 2001 | 2.8 | 3.33 | 1.79 |
| 2000 | 2.85 | 3.98 | 2.11 |
| 1999 | 2.2 | 2.93 | 1.74 |
| 1998 | 1.81 | 2.22 | 1.41 |