| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | ||
| 2021 | 0 | ||
| 2020 | 0 | -0.18 | |
| 2019 | 5.8 | 13.03 | 0.78 |
| 2018 | 1.53 | 2.48 | 0.55 |
| 2017 | 3.2 | 4.15 | 2.37 |
| 2016 | 5.63 | 9.18 | 3.56 |
| 2015 | 13.8 | 37.5 | 5.37 |
| 2014 | 5.97 | 10.92 | 4.66 |
| 2013 | 5.08 | 6.18 | 3.6 |
| 2012 | 3.17 | 3.59 | 2.43 |
| 2011 | 3.46 | 4.11 | 2.29 |
| 2010 | 3.84 | 4.84 | 3.12 |
| 2009 | 2.9 | 4.28 | 1.27 |
| 2008 | 1.97 | 2.92 | 0.85 |
| 2007 | 2.62 | 4.77 | 1.81 |
| 2006 | 1.4 | 2.19 | 0.89 |
| 2005 | 0.51 | 0.95 | 0.28 |
| 2004 | 0.76 | 1.04 | 0.55 |
| 2003 | 0.89 | 0.98 | 0.77 |
| 2002 | 1.22 | 1.54 | 0.88 |
| 2001 | 0.9 | 1.67 | 0.25 |
| 2000 | 0.21 | 0.29 | 0.15 |
| 1999 | 0.16 | 0.35 | 0.06 |
| 1998 | 0.11 | 0.14 | 0.06 |
| 1997 | 0.2 | 0.29 | 0.12 |