| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.91 | 2.22 | 1.61 |
| 2024 | 2.12 | 2.94 | 1.51 |
| 2023 | 3.43 | 5.09 | 2.38 |
| 2022 | 3.17 | 5.26 | 1.49 |
| 2021 | 2.39 | 4.4 | 1.48 |
| 2020 | 1.44 | 2.36 | 0.96 |
| 2019 | 1.48 | 1.96 | 1.12 |
| 2018 | 2.2 | 3.88 | 1.37 |
| 2017 | 3.95 | 4.57 | 3.12 |
| 2016 | 4.39 | 5.16 | 3.65 |
| 2015 | 5.32 | 11.5 | 2.58 |
| 2014 | 2.04 | 3.93 | 1.14 |
| 2013 | 1.26 | 1.48 | 1.1 |
| 2012 | 1.31 | 1.69 | 0.99 |
| 2011 | 2.07 | 2.65 | 1.23 |
| 2010 | 2.12 | 2.56 | 1.71 |
| 2009 | 1.56 | 2.28 | 0.83 |
| 2008 | 1.45 | 2.61 | 0.66 |
| 2007 | 2.1 | 3.12 | 0.87 |
| 2006 | 0.83 | 0.97 | 0.67 |
| 2005 | 0.92 | 1.22 | 0.61 |
| 2004 | 1.5 | 1.89 | 1.21 |
| 2003 | 1.77 | 2.08 | 1.41 |
| 2002 | 2.77 | 3.69 | 2.26 |
| 2001 | 4.66 | 6.39 | 3.18 |
| 2000 | 4.79 | 5.73 | 3.4 |
| 1999 | 4.02 | 4.88 | 3 |