| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.43 | 2.6 | 2.24 |
| 2024 | 2.54 | 2.94 | 1.94 |
| 2023 | 3.99 | 5.32 | 2.61 |
| 2022 | 3.76 | 4.09 | 3.1 |
| 2021 | 4.14 | 4.97 | 3.5 |
| 2020 | 3.62 | 4.45 | 2.55 |
| 2019 | 2.81 | 3.44 | 2 |
| 2018 | 2.61 | 3.4 | 2.03 |
| 2017 | 2.37 | 3.12 | 2.04 |
| 2016 | 2.24 | 2.63 | 1.84 |
| 2015 | 2.14 | 2.74 | 1.69 |
| 2014 | 1.64 | 2 | 1.25 |
| 2013 | 1.79 | 2.76 | 1.3 |
| 2012 | 3.14 | 4.75 | 1.76 |
| 2011 | 5.21 | 7.18 | 3.6 |
| 2010 | 4.32 | 6.38 | 3.04 |
| 2009 | 1.39 | 2.95 | 0.53 |
| 2008 | 1.11 | 2.33 | 0.38 |
| 2007 | 1.84 | 3.11 | 1.17 |
| 2006 | 1.03 | 1.43 | 0.7 |
| 2005 | 0.26 | 0.77 | 0.11 |
| 2004 | 0.26 | 0.52 | 0.16 |