| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.94 | 2.04 | 1.85 |
| 2024 | 2.12 | 2.36 | 1.83 |
| 2023 | 2.87 | 3.87 | 1.95 |
| 2022 | 3.94 | 5.92 | 3.15 |
| 2021 | 3.42 | 5.12 | 2.51 |
| 2020 | 4.43 | 5.24 | 3.59 |
| 2019 | 4.67 | 5.69 | 3.36 |
| 2018 | 3.9 | 4.62 | 3.24 |
| 2017 | 3.04 | 3.66 | 2.38 |
| 2016 | 2.56 | 2.88 | 2.34 |
| 2015 | 2.79 | 4.06 | 1.98 |
| 2014 | 1.59 | 2.19 | 1.4 |
| 2013 | 1.65 | 2.03 | 1.37 |
| 2012 | 1.56 | 1.7 | 1.37 |
| 2011 | 1.79 | 2.1 | 1.53 |
| 2010 | 2.19 | 3.15 | 1.66 |
| 2009 | 2.29 | 2.81 | 1.84 |
| 2008 | 3.38 | 6.86 | 1.66 |
| 2007 | 6.15 | 7.79 | 3.87 |
| 2006 | 2.93 | 3.65 | 2.4 |
| 2005 | 3.71 | 4.3 | 2.84 |
| 2004 | 3.61 | 4.13 | 3.07 |
| 2003 | 2.81 | 3.31 | 2.53 |
| 2002 | 2.53 | 2.72 | 2.24 |
| 2001 | 2.89 | 3.43 | 2.22 |
| 2000 | 3.38 | 3.75 | 3.11 |
| 1999 | 4.39 | 5.97 | 3.61 |