| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.6 | 1.96 | 1.42 |
| 2024 | 1.38 | 1.89 | 1.09 |
| 2023 | 1.69 | 2.16 | 1.45 |
| 2022 | 1.7 | 2.43 | 1.34 |
| 2021 | 1.68 | 2.24 | 1.29 |
| 2020 | 1.75 | 2.2 | 1.33 |
| 2019 | 1.63 | 2.06 | 1.29 |
| 2018 | 1.68 | 2.73 | 1.01 |
| 2017 | 5 | 7.43 | 2.39 |
| 2016 | 5.36 | 6.94 | 3.94 |
| 2015 | 6.79 | 12.78 | 3.31 |
| 2014 | 5.04 | 8.7 | 2.85 |
| 2013 | 2.88 | 3.48 | 2.29 |
| 2012 | 2.7 | 3.46 | 2.14 |
| 2011 | 6.79 | 12.85 | 2.74 |
| 2010 | 10.42 | 12.95 | 7.79 |
| 2009 | 17.95 | 34.14 | 7 |
| 2008 | 18.01 | 19.61 | 15.36 |
| 2007 | 0 | -1.55 | |
| 2006 | 1.17 | 1.35 | 0.95 |
| 2005 | 1.59 | 2.33 | 1 |
| 2004 | 2.79 | 3.73 | 2.06 |
| 2003 | 3.18 | 4.04 | 2.44 |
| 2002 | 5.24 | 5.93 | 4.65 |
| 2001 | 8.47 | 11.99 | 5.47 |
| 2000 | 9.76 | 12.27 | 8.41 |