| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.51 | 1.69 | 1.26 |
| 2024 | 1.61 | 1.81 | 1.42 |
| 2023 | 1.71 | 2.02 | 1.54 |
| 2022 | 1.57 | 1.91 | 1.34 |
| 2021 | 2.01 | 2.22 | 1.81 |
| 2020 | 3 | 6.61 | 1.72 |
| 2019 | 1.81 | 2.55 | 1.34 |
| 2018 | 1.7 | 2.5 | 1.06 |
| 2017 | 2.27 | 3.07 | 1.95 |
| 2016 | 2.31 | 2.8 | 1.98 |
| 2015 | 3.45 | 5.31 | 2.44 |
| 2014 | 2.07 | 3.02 | 1.72 |
| 2013 | 2.4 | 3.16 | 1.47 |
| 2012 | 1.76 | 2.41 | 1.18 |
| 2011 | 2.47 | 3.48 | 1.43 |
| 2010 | 3.92 | 6.03 | 2.88 |
| 2009 | 4.04 | 6.32 | 1.92 |
| 2008 | 3.17 | 7.04 | 1.26 |
| 2007 | 3.91 | 7.2 | 1.28 |
| 2006 | 1.01 | 1.2 | 0.81 |
| 2005 | 0.95 | 1.27 | 0.73 |
| 2004 | 2.33 | 4.1 | 1.14 |
| 2003 | 3.41 | 4.46 | 2.71 |
| 2002 | 1.9 | 2.3 | 1.38 |
| 2001 | 2.13 | 2.55 | 1.68 |
| 2000 | 1.93 | 2.42 | 1.55 |
| 1999 | 2.05 | 2.68 | 1.57 |
| 1998 | 2.98 | 4 | 2.21 |