| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.31 | 1.37 | 1.19 |
| 2024 | 0.95 | 1.45 | 0.88 |
| 2023 | 1.18 | 1.36 | 0.91 |
| 2022 | 1.12 | 1.31 | 0.81 |
| 2021 | 1.05 | 1.26 | 0.85 |
| 2020 | 0.88 | 1.12 | 0.76 |
| 2019 | 0.77 | 0.89 | 0.64 |
| 2018 | 0.73 | 0.81 | 0.63 |
| 2017 | 0.91 | 1.42 | 0.74 |
| 2016 | 1.5 | 2.36 | 0.95 |
| 2015 | 1.88 | 2.34 | 1.12 |
| 2014 | 1.29 | 1.62 | 1.08 |
| 2013 | 1.8 | 2.43 | 1.42 |
| 2012 | 1.5 | 1.83 | 1.09 |
| 2011 | 1.96 | 2.76 | 1.28 |
| 2010 | 2.47 | 2.97 | 1.92 |
| 2009 | 2.02 | 2.84 | 1.38 |
| 2008 | 2.4 | 5.52 | 0.99 |
| 2007 | 5.42 | 6.76 | 3.76 |
| 2006 | 3.2 | 4.09 | 2.32 |
| 2005 | 1.52 | 3.48 | 1.02 |
| 2004 | 1.08 | 1.26 | 0.92 |
| 2003 | 0.79 | 1.14 | 0.61 |
| 2002 | 0.88 | 1.07 | 0.65 |
| 2001 | 1.25 | 2.11 | 0.53 |
| 2000 | 0.6 | 0.8 | 0.41 |
| 1999 | 0.58 | 1.06 | 0.25 |