| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | -0.16 | |
| 2022 | 33.25 | 46.92 | 13.99 |
| 2021 | 5.92 | 21.35 | 0.48 |
| 2020 | 0.57 | 0.84 | 0.26 |
| 2019 | 0.57 | 0.79 | 0.44 |
| 2018 | 1.03 | 1.32 | 0.53 |
| 2017 | 1.56 | 1.88 | 1.21 |
| 2016 | 2.38 | 3.21 | 1.6 |
| 2015 | 1.99 | 3.23 | 1.23 |
| 2014 | 1.07 | 1.48 | 0.73 |
| 2013 | 0.81 | 1.01 | 0.66 |
| 2012 | 0.97 | 1.34 | 0.73 |
| 2011 | 1.77 | 2.79 | 1.09 |
| 2010 | 2.64 | 3.71 | 1.9 |
| 2009 | 3.02 | 4.41 | 2.2 |
| 2008 | 4.43 | 8.49 | 1.77 |
| 2007 | 4.46 | 7.34 | 2.32 |
| 2006 | 1.87 | 2.72 | 1.24 |
| 2005 | 1.39 | 1.85 | 1.12 |
| 2004 | 1.99 | 2.55 | 1.6 |
| 2003 | 2.26 | 2.75 | 1.71 |
| 2002 | 3.99 | 6.2 | 2.95 |
| 2001 | 7.73 | 9.64 | 5.65 |
| 2000 | 8.67 | 11.04 | 6.83 |
| 1999 | 6.4 | 9.25 | 4.73 |