| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0 | -0.37 | |
| 2025 | 0 | -0.19 | |
| 2024 | 1.84 | 3.71 | 0.54 |
| 2023 | 0.64 | 1.15 | 0.21 |
| 2022 | 0.45 | 0.71 | 0.26 |
| 2021 | 0.88 | 1.37 | 0.53 |
| 2020 | 1.56 | 1.98 | 1.21 |
| 2019 | 1.52 | 1.89 | 1.33 |
| 2018 | 1.42 | 1.59 | 1.19 |
| 2017 | 1.51 | 1.82 | 1.24 |
| 2016 | 1.38 | 1.83 | 1.1 |
| 2015 | 2.52 | 4.45 | 1.53 |
| 2014 | 1.39 | 2.89 | 0.96 |
| 2013 | 1.94 | 2.72 | 1.17 |
| 2012 | 2.62 | 4.23 | 1.53 |
| 2011 | 9.88 | 37.64 | 0.73 |
| 2010 | 6.04 | 9.45 | 4.37 |
| 2009 | 6.22 | 11.01 | 2.28 |
| 2008 | 3.96 | 6.19 | 1.67 |
| 2007 | 6.23 | 8.75 | 2.94 |
| 2006 | 2.18 | 3.12 | 1.27 |
| 2005 | 1.24 | 1.59 | 0.88 |
| 2004 | 2.55 | 4.8 | 1.35 |
| 2003 | 4.38 | 5.39 | 3.29 |
| 2002 | 4.81 | 6.07 | 3.22 |
| 2001 | 7.87 | 10.73 | 4.46 |
| 2000 | 7 | 8.73 | 4.22 |
| 1999 | 5.06 | 6.26 | 4.07 |
| 1998 | 5.21 | 6.95 | 3.44 |
| 1997 | 5.06 | 7.57 | 3.49 |