| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.36 | 2.8 | 2.12 |
| 2024 | 1.92 | 2.68 | 1.54 |
| 2023 | 2.03 | 2.23 | 1.83 |
| 2022 | 2.15 | 2.52 | 1.88 |
| 2021 | 2.13 | 2.69 | 1.8 |
| 2020 | 2.85 | 3.83 | 2.17 |
| 2019 | 3.06 | 4.02 | 2.63 |
| 2018 | 3.93 | 5.91 | 2.53 |
| 2017 | 6.32 | 7.4 | 5.17 |
| 2016 | 8.25 | 11.75 | 7.14 |
| 2015 | 10.3 | 16.99 | 5.95 |
| 2014 | 5.65 | 8.25 | 2.23 |
| 2013 | 2.44 | 3.07 | 1.95 |
| 2012 | 2.21 | 2.94 | 1.73 |
| 2011 | 3.74 | 5.05 | 2.37 |
| 2010 | 6.15 | 9.62 | 4.35 |
| 2009 | 4.5 | 5.67 | 1.72 |
| 2008 | 3.99 | 8.93 | 1.53 |
| 2007 | 6.08 | 9.91 | 2.56 |
| 2006 | 2.16 | 2.74 | 1.65 |
| 2005 | 2.03 | 2.34 | 1.72 |
| 2004 | 2.2 | 2.96 | 1.08 |
| 2003 | 2.75 | 3.35 | 2.26 |
| 2002 | 3.59 | 5.36 | 2.51 |
| 2001 | 5.36 | 6.19 | 4.24 |
| 2000 | 4.8 | 5.92 | 3.56 |
| 1999 | 4.48 | 6.45 | 3.15 |
| 1998 | 5.63 | 8.58 | 3.44 |
| 1997 | 7.41 | 9.84 | 5.29 |