| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.89 | 2.52 | 1.31 |
| 2025 | 1.25 | 1.5 | 1.06 |
| 2024 | 1.41 | 2.13 | 0.9 |
| 2023 | 1.64 | 2.44 | 1.35 |
| 2022 | 1.51 | 2.02 | 1.13 |
| 2021 | 1.29 | 1.56 | 0.96 |
| 2020 | 1.42 | 1.73 | 1.17 |
| 2019 | 1.65 | 1.98 | 1.42 |
| 2018 | 2.12 | 2.55 | 1.65 |
| 2017 | 2.69 | 3.33 | 2.17 |
| 2016 | 3.15 | 4.25 | 2.62 |
| 2015 | 3.03 | 4.21 | 1.82 |
| 2014 | 1.6 | 1.99 | 1.37 |
| 2013 | 1.8 | 2.44 | 1.4 |
| 2012 | 2.89 | 4.23 | 1.85 |
| 2011 | 5.06 | 6.36 | 3.86 |
| 2010 | 6.84 | 8.56 | 5.78 |
| 2009 | 4.54 | 6.46 | 2.65 |
| 2008 | 3.48 | 5.45 | 2.09 |
| 2007 | 4.04 | 5.62 | 1.98 |
| 2006 | 1.84 | 2.23 | 1.41 |
| 2005 | 1.31 | 1.63 | 1.09 |
| 2004 | 1.95 | 3.68 | 1.39 |
| 2003 | 2.29 | 3.19 | 1.83 |
| 2002 | 2.73 | 3.22 | 2.32 |
| 2001 | 5.56 | 7.16 | 3.94 |
| 2000 | 5.18 | 6.08 | 3.49 |
| 1999 | 4.26 | 6.08 | 3.04 |
| 1998 | 3.85 | 4.67 | 2.95 |