| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.21 | 1.36 | 1.07 |
| 2024 | 1.29 | 1.92 | 0.83 |
| 2023 | 0.88 | 1.69 | 0.61 |
| 2022 | 0.71 | 0.9 | 0.6 |
| 2021 | 0.84 | 1 | 0.68 |
| 2020 | 0.97 | 1.2 | 0.71 |
| 2019 | 1.05 | 1.45 | 0.84 |
| 2018 | 1.64 | 2.73 | 0.79 |
| 2017 | 2.69 | 3.58 | 2.04 |
| 2016 | 3.09 | 4.96 | 2.62 |
| 2015 | 4.7 | 7.18 | 2.66 |
| 2014 | 3.34 | 5.21 | 2.56 |
| 2013 | 3.48 | 4.66 | 2.28 |
| 2012 | 4.26 | 6.33 | 3.11 |
| 2011 | 5.28 | 6.09 | 4.51 |
| 2010 | 5.48 | 7.06 | 3.68 |
| 2009 | 2.22 | 3.82 | 1.17 |
| 2008 | 2.33 | 5.08 | 0.94 |
| 2007 | 3.74 | 6.04 | 1.82 |
| 2006 | 1.84 | 3.05 | 1.24 |
| 2005 | 1.54 | 2.18 | 1.08 |
| 2004 | 2.42 | 3.32 | 1.88 |
| 2003 | 3.17 | 4.11 | 2.17 |
| 2002 | 5.18 | 6.74 | 4.17 |
| 2001 | 8.46 | 10.39 | 6.47 |
| 2000 | 15.09 | 19.13 | 11.83 |
| 1999 | 8.89 | 12.79 | 6.78 |