| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.04 | 1.37 | 0.95 |
| 2024 | 0.81 | 1.36 | 0.61 |
| 2023 | 0.79 | 0.9 | 0.73 |
| 2022 | 0.81 | 0.95 | 0.69 |
| 2021 | 0.84 | 0.98 | 0.75 |
| 2020 | 0.98 | 1.22 | 0.83 |
| 2019 | 1.24 | 1.65 | 0.99 |
| 2018 | 1.19 | 1.42 | 0.99 |
| 2017 | 1.62 | 2.13 | 1.33 |
| 2016 | 1.5 | 1.72 | 1.26 |
| 2015 | 1.85 | 3.07 | 1.23 |
| 2014 | 1.26 | 1.86 | 1.06 |
| 2013 | 1.27 | 1.57 | 1.01 |
| 2012 | 1.24 | 1.49 | 1.01 |
| 2011 | 1.67 | 1.98 | 1.12 |
| 2010 | 2.03 | 2.73 | 1.51 |
| 2009 | 1.86 | 2.54 | 1.36 |
| 2008 | 1.9 | 3.88 | 0.9 |
| 2007 | 2.2 | 3.44 | 1.12 |
| 2006 | 1.21 | 1.66 | 1.02 |
| 2005 | 1.23 | 1.57 | 0.98 |
| 2004 | 2.13 | 2.9 | 1.53 |
| 2003 | 2.93 | 3.58 | 2.11 |
| 2002 | 4.09 | 4.77 | 3.18 |
| 2001 | 5.51 | 6.46 | 4.18 |