| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.78 | 1.3 | 0.59 |
| 2024 | 0.7 | 0.97 | 0.48 |
| 2023 | 0.64 | 0.74 | 0.57 |
| 2022 | 0.69 | 0.84 | 0.56 |
| 2021 | 0.7 | 0.79 | 0.63 |
| 2020 | 1.18 | 1.61 | 0.75 |
| 2019 | 1.32 | 2.03 | 0.74 |
| 2018 | 1.2 | 1.64 | 0.78 |
| 2017 | 1.79 | 2.06 | 1.53 |
| 2016 | 3.22 | 4.53 | 2.05 |
| 2015 | 5.16 | 9.8 | 2.8 |
| 2014 | 3.49 | 6.21 | 2.69 |
| 2013 | 3.52 | 4.9 | 2.88 |
| 2012 | 3.8 | 5.17 | 3.04 |
| 2011 | 4.25 | 6.37 | 3.02 |
| 2010 | 0 | ||
| 2009 | 0 | ||
| 2008 | 0 | -1.79 | |
| 2007 | 3.04 | 4.41 | 1.99 |
| 2006 | 1.55 | 2.32 | 0.81 |
| 2005 | 0.62 | 0.92 | 0.43 |
| 2004 | 1.01 | 1.54 | 0.67 |
| 2003 | 1.53 | 1.97 | 1.15 |
| 2002 | 2.01 | 2.21 | 1.52 |
| 2001 | 2.78 | 3.35 | 1.86 |
| 2000 | 4.7 | 5.52 | 3.98 |
| 1999 | 2.83 | 4.52 | 1.68 |
| 1998 | 2.13 | 2.67 | 1.55 |