| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.17 | 1.23 | 1.08 |
| 2024 | 1.24 | 1.47 | 1.03 |
| 2023 | 1.06 | 1.17 | 0.99 |
| 2022 | 1.13 | 1.46 | 0.99 |
| 2021 | 1.26 | 1.44 | 1.12 |
| 2020 | 1.28 | 1.41 | 1.08 |
| 2019 | 1.3 | 1.49 | 1.16 |
| 2018 | 1.38 | 1.73 | 1.16 |
| 2017 | 1.86 | 2.07 | 1.64 |
| 2016 | 2.03 | 2.44 | 1.81 |
| 2015 | 3.19 | 4.99 | 2.08 |
| 2014 | 2.28 | 3.27 | 1.94 |
| 2013 | 2.66 | 4.02 | 1.99 |
| 2012 | 2.37 | 2.87 | 1.82 |
| 2011 | 3.97 | 7.31 | 2.57 |
| 2010 | 7.23 | 16.41 | 5.3 |
| 2009 | 4.61 | 7.35 | 1.94 |
| 2008 | 3.86 | 7.02 | 1.43 |
| 2007 | 5 | 8.59 | 1.71 |
| 2006 | 1.74 | 2.5 | 0.92 |
| 2005 | 1 | 1.26 | 0.71 |
| 2004 | 1.49 | 2.5 | 1.01 |
| 2003 | 1.87 | 2.23 | 1.37 |
| 2002 | 2.53 | 3.97 | 1.7 |
| 2001 | 3.83 | 4.56 | 2.73 |
| 2000 | 4.18 | 4.85 | 3.69 |
| 1999 | 4.24 | 6.43 | 2.59 |
| 1998 | 4.11 | 5.45 | 2.91 |
| 1997 | 5.66 | 6.99 | 4.34 |