| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0 | ||
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | -0.08 | |
| 2021 | 1.01 | 1.19 | 0.81 |
| 2020 | 1.68 | 2.34 | 1.05 |
| 2019 | 1.87 | 3.14 | 1.22 |
| 2018 | 1.93 | 3.23 | 1.12 |
| 2017 | 2.27 | 2.7 | 1.77 |
| 2016 | 2.67 | 3.07 | 2.35 |
| 2015 | 12.15 | 38.86 | 2.17 |
| 2014 | 5.56 | 9.38 | 4.37 |
| 2013 | 5.04 | 5.8 | 4.37 |
| 2012 | 4.52 | 5.5 | 3.78 |
| 2011 | 6.35 | 7.78 | 3.98 |
| 2010 | 7.37 | 9.73 | 5.56 |
| 2009 | 6.72 | 8.54 | 4.82 |
| 2008 | 7.03 | 12.66 | 3.77 |
| 2007 | 5.34 | 8.74 | 1.8 |
| 2006 | 1.67 | 2.21 | 1.19 |
| 2005 | 1.62 | 2.34 | 1.2 |
| 2004 | 2.99 | 4.37 | 2.2 |
| 2003 | 4.49 | 6.39 | 3.01 |
| 2002 | 5.95 | 6.83 | 4.74 |
| 2001 | 6.24 | 7.94 | 4.74 |
| 2000 | 4.95 | 6.14 | 4.03 |
| 1999 | 3.61 | 4.71 | 2.88 |
| 1998 | 3.85 | 4.87 | 2.94 |