| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.33 | 1.78 | 1.14 |
| 2024 | 1.21 | 1.4 | 1.03 |
| 2023 | 1.51 | 1.77 | 1.31 |
| 2022 | 1.42 | 1.81 | 1.17 |
| 2021 | 2.01 | 2.54 | 1.5 |
| 2020 | 1.94 | 3.11 | 1.32 |
| 2019 | 1.39 | 2.35 | 1.16 |
| 2018 | 1.57 | 2.02 | 1.18 |
| 2017 | 2.3 | 3.03 | 1.85 |
| 2016 | 2.47 | 3.48 | 1.94 |
| 2015 | 3.44 | 6.16 | 1.99 |
| 2014 | 2.09 | 2.69 | 1.68 |
| 2013 | 1.97 | 2.4 | 1.69 |
| 2012 | 2.77 | 3.74 | 1.58 |
| 2011 | 4.78 | 6.64 | 3.64 |
| 2010 | 4.9 | 6.54 | 3.79 |
| 2009 | 3.17 | 4.68 | 1.92 |
| 2008 | 3.83 | 7.53 | 1.45 |
| 2007 | 6.77 | 10.39 | 2.9 |
| 2006 | 2.61 | 3.25 | 1.91 |
| 2005 | 1.75 | 2.28 | 1.19 |
| 2004 | 2.84 | 4.15 | 1.79 |
| 2003 | 4.42 | 5.35 | 3.42 |
| 2002 | 5.3 | 5.94 | 4.95 |
| 2001 | 5.64 | 6.87 | 4.47 |
| 2000 | 4.03 | 5.19 | 2.49 |
| 1999 | 2.77 | 3.62 | 2.14 |
| 1998 | 3.78 | 5.29 | 2.66 |
| 1997 | 5.04 | 6.38 | 3.96 |