| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0.4 | 0.59 | 0.28 |
| 2022 | 0.43 | 0.67 | 0.3 |
| 2021 | 0.41 | 0.49 | 0.33 |
| 2020 | 0.62 | 0.92 | 0.46 |
| 2019 | 0.84 | 1.32 | 0.62 |
| 2018 | 1.47 | 2.88 | 0.85 |
| 2017 | 1.43 | 1.67 | 1.12 |
| 2016 | 2 | 3.13 | 1.58 |
| 2015 | 5.21 | 9.62 | 2.92 |
| 2014 | 3.15 | 4.59 | 2.7 |
| 2013 | 4.08 | 5.45 | 3.01 |
| 2012 | 3.27 | 3.82 | 2.82 |
| 2011 | 4.78 | 6.65 | 2.74 |
| 2010 | 5.68 | 8.79 | 4.37 |
| 2009 | 0 | ||
| 2008 | 0 | ||
| 2007 | 0 | -0.41 | |
| 2006 | 0.92 | 1.11 | 0.71 |
| 2005 | 1.05 | 1.25 | 0.73 |
| 2004 | 1.65 | 2.45 | 1.16 |
| 2003 | 2.05 | 2.47 | 1.7 |
| 2002 | 2.76 | 3.12 | 1.74 |
| 2001 | 4.07 | 5.16 | 2.74 |
| 2000 | 4.52 | 6.58 | 3.52 |
| 1999 | 3.78 | 5.14 | 2.66 |
| 1998 | 3.78 | 4.72 | 2.8 |