| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | -0.35 | |
| 2022 | 6.1 | 8.07 | 4.39 |
| 2021 | 2.49 | 10.28 | 0.45 |
| 2020 | 2.09 | 2.63 | 1.62 |
| 2019 | 2.38 | 3.21 | 1.85 |
| 2018 | 3.64 | 5.54 | 1.96 |
| 2017 | 4.89 | 6.59 | 3.52 |
| 2016 | 3.14 | 4.11 | 2.1 |
| 2015 | 4.04 | 9.56 | 1.88 |
| 2014 | 2.24 | 3.18 | 1.84 |
| 2013 | 2.46 | 3.17 | 2 |
| 2012 | 3.29 | 4.83 | 1.82 |
| 2011 | 2.46 | 2.98 | 1.84 |
| 2010 | 2.45 | 3.21 | 1.86 |
| 2009 | 2.16 | 3.01 | 0.97 |
| 2008 | 1.63 | 3.46 | 0.74 |
| 2007 | 2.68 | 3.55 | 1.62 |
| 2006 | 1.46 | 1.98 | 0.84 |
| 2005 | 1.08 | 1.43 | 0.77 |
| 2004 | 1.73 | 2.28 | 1.03 |
| 2003 | 1.93 | 2.7 | 1.39 |
| 2002 | 4.02 | 4.93 | 3.58 |
| 2001 | 5.91 | 7.28 | 4.49 |