| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | ||
| 2021 | 1.31 | 1.36 | 1.28 |
| 2020 | 1.26 | 1.51 | 1.08 |
| 2019 | 1.47 | 1.81 | 1.31 |
| 2018 | 1.6 | 2.07 | 1.27 |
| 2017 | 2.15 | 2.56 | 2 |
| 2016 | 2.32 | 2.94 | 2.08 |
| 2015 | 3.65 | 5.11 | 2.9 |
| 2014 | 1.89 | 3.98 | 0.71 |
| 2013 | 0.8 | 0.91 | 0.69 |
| 2012 | 0.99 | 1.8 | 0.79 |
| 2011 | 1.48 | 2.18 | 0.92 |
| 2010 | 2.35 | 3.17 | 1.85 |
| 2009 | 2.07 | 3.18 | 1.13 |
| 2008 | 2.01 | 3.35 | 1.01 |
| 2007 | 3.01 | 5.24 | 2.08 |
| 2006 | 1.9 | 2.27 | 1.41 |
| 2005 | 2.19 | 2.58 | 1.77 |
| 2004 | 2.37 | 2.77 | 2.03 |
| 2003 | 2.59 | 3.06 | 1.99 |