| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.27 | 1.54 | 1.16 |
| 2024 | 1.17 | 1.56 | 0.73 |
| 2023 | 1.13 | 1.24 | 1.01 |
| 2022 | 1.44 | 1.96 | 1.12 |
| 2021 | 1.75 | 3.16 | 1.28 |
| 2020 | 1.93 | 2.66 | 1.38 |
| 2019 | 1.81 | 2.35 | 1.53 |
| 2018 | 2.29 | 3.13 | 1.54 |
| 2017 | 3.19 | 3.82 | 2.27 |
| 2016 | 2.97 | 3.54 | 2.28 |
| 2015 | 3.03 | 5.91 | 1.86 |
| 2014 | 1.72 | 2.32 | 1.44 |
| 2013 | 1.57 | 1.87 | 1.28 |
| 2012 | 1.81 | 2.25 | 1.32 |
| 2011 | 2.24 | 2.8 | 1.6 |
| 2010 | 1.53 | 1.68 | 1.32 |
| 2009 | 1.21 | 1.74 | 0.68 |
| 2008 | 1.04 | 1.8 | 0.54 |
| 2007 | 1.17 | 1.78 | 0.69 |
| 2006 | 0.68 | 0.96 | 0.49 |
| 2005 | 0.66 | 0.89 | 0.5 |
| 2004 | 1.11 | 1.33 | 0.8 |
| 2003 | 1.23 | 1.44 | 1.07 |
| 2002 | 1.93 | 2.34 | 1.73 |
| 2001 | 2.73 | 3.32 | 2.17 |
| 2000 | 5.61 | 6.83 | 4.59 |
| 1999 | 6.68 | 9.5 | 5.54 |
| 1998 | 10.77 | 15.42 | 8.18 |
| 1997 | 7.88 | 11.05 | 4.96 |