| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.75 | 2.1 | 1.33 |
| 2023 | 2.03 | 2.88 | 1.44 |
| 2022 | 2.98 | 3.63 | 2.52 |
| 2021 | 2.23 | 3.49 | 1.6 |
| 2020 | 2.92 | 3.9 | 2.19 |
| 2019 | 3.07 | 3.98 | 2.65 |
| 2018 | 4.07 | 5.88 | 2.75 |
| 2017 | 7.11 | 10.52 | 5.31 |
| 2016 | 10.74 | 95.3 | 3.88 |
| 2015 | 2.87 | 4.58 | 1.62 |
| 2014 | 1.63 | 2.29 | 1.32 |
| 2013 | 1.63 | 2.27 | 1.39 |
| 2012 | 1.77 | 2.28 | 1.2 |
| 2011 | 2.93 | 3.85 | 1.77 |
| 2010 | 3.58 | 4.51 | 2.59 |
| 2009 | 2.56 | 4.83 | 1.15 |
| 2008 | 2.16 | 4.55 | 0.89 |
| 2007 | 3.15 | 4.4 | 1.29 |
| 2006 | 1.17 | 1.39 | 0.96 |
| 2005 | 1.27 | 1.61 | 0.95 |
| 2004 | 1.95 | 2.85 | 1.49 |
| 2003 | 2.79 | 3.81 | 2.08 |
| 2002 | 4.92 | 5.49 | 3.49 |
| 2001 | 6.15 | 7.47 | 4.53 |