| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.65 | 3.2 | 2.34 |
| 2024 | 2.2 | 3.16 | 1.53 |
| 2023 | 2.42 | 3.58 | 1.94 |
| 2022 | 2.45 | 3.49 | 1.77 |
| 2021 | 25.22 | 94.41 | 3.31 |
| 2020 | 22.29 | 83.27 | 11.55 |
| 2019 | 12.58 | 18.24 | 11.01 |
| 2018 | 13.57 | 21.32 | 8.94 |
| 2017 | 25.26 | 37 | 19.48 |
| 2016 | 27.72 | 38.77 | 23.11 |
| 2015 | 18.45 | 23.15 | 13.83 |
| 2014 | 14.31 | 20.45 | 10.06 |
| 2013 | 14.44 | 21.75 | 10 |
| 2012 | 0 | ||
| 2011 | 0 | ||
| 2010 | 0 | -0.28 | |
| 2009 | 0 | -0.17 | |
| 2008 | 4.1 | 5.6 | 1.95 |
| 2007 | 5.32 | 7.57 | 3.87 |
| 2006 | 4.67 | 6.67 | 3.63 |
| 2005 | 4.97 | 6.19 | 3.75 |
| 2004 | 10.08 | 17.69 | 5.8 |
| 2003 | 17.11 | 22.74 | 11.1 |
| 2002 | 21.82 | 27.75 | 13.8 |
| 2001 | 22.57 | 28.2 | 19.38 |
| 2000 | 27.78 | 45.35 | 11.84 |
| 1999 | 12.34 | 15.19 | 10.03 |
| 1998 | 8.72 | 12.04 | 6.42 |
| 1997 | 6.11 | 8.78 | 4.65 |