| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.03 | 1.42 | 0.88 |
| 2024 | 0.89 | 1.03 | 0.75 |
| 2023 | 0.94 | 1.26 | 0.77 |
| 2022 | 1.01 | 1.25 | 0.91 |
| 2021 | 1.24 | 1.47 | 1.02 |
| 2020 | 1.32 | 1.59 | 1.01 |
| 2019 | 1.2 | 1.66 | 1 |
| 2018 | 1.43 | 1.89 | 1.1 |
| 2017 | 1.84 | 2.02 | 1.58 |
| 2016 | 1.73 | 2.05 | 1.41 |
| 2015 | 2.65 | 3.61 | 1.79 |
| 2014 | 2.69 | 3.34 | 2.38 |
| 2013 | 2.9 | 3.69 | 2.29 |
| 2012 | 2.88 | 5.02 | 1.97 |
| 2011 | 4.97 | 8.25 | 3.41 |
| 2010 | 4.03 | 7 | 2.5 |
| 2009 | 2.58 | 4.07 | 1.22 |
| 2008 | 2.73 | 6.11 | 0.95 |
| 2007 | 4.12 | 5.6 | 2.05 |
| 2006 | 1.53 | 2.18 | 1.15 |
| 2005 | 1.43 | 1.98 | 1.04 |
| 2004 | 1.79 | 2.59 | 1.15 |
| 2003 | 2.1 | 2.35 | 1.84 |
| 2002 | 2.27 | 2.46 | 1.9 |
| 2001 | 2.49 | 3.21 | 1.73 |
| 2000 | 2.63 | 3.93 | 1.78 |
| 1999 | 1.81 | 2.69 | 1.24 |