| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.16 | 1.27 | 1.09 |
| 2024 | 1.01 | 1.85 | 0.83 |
| 2023 | 1.12 | 1.23 | 1.03 |
| 2022 | 1.09 | 1.43 | 0.94 |
| 2021 | 1.19 | 1.33 | 1.07 |
| 2020 | 1.54 | 2.29 | 1.09 |
| 2019 | 1.13 | 1.51 | 0.91 |
| 2018 | 1.16 | 1.59 | 0.87 |
| 2017 | 1.9 | 2.51 | 1.49 |
| 2016 | 2.78 | 3.73 | 2.34 |
| 2015 | 3.13 | 4.7 | 2.04 |
| 2014 | 1.97 | 2.39 | 1.63 |
| 2013 | 1.64 | 2.16 | 1.28 |
| 2012 | 1.79 | 2.17 | 1.47 |
| 2011 | 2.76 | 3.64 | 1.91 |
| 2010 | 4.21 | 5.77 | 3.03 |
| 2009 | 3.54 | 4.67 | 2.32 |
| 2008 | 3.59 | 6.29 | 1.92 |
| 2007 | 5.91 | 9.21 | 3.91 |
| 2006 | 2.9 | 4.03 | 2.29 |
| 2005 | 2.14 | 2.61 | 1.68 |
| 2004 | 2.06 | 2.73 | 1.54 |
| 2003 | 2.45 | 2.86 | 1.91 |
| 2002 | 3.06 | 3.58 | 2.36 |
| 2001 | 3.67 | 4.77 | 2.7 |
| 2000 | 4.97 | 5.92 | 3.45 |
| 1999 | 3.67 | 4.58 | 3.06 |
| 1998 | 4.38 | 5.28 | 3.42 |
| 1997 | 5.56 | 7.54 | 4.58 |