| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 7.19 | 7.36 | 6.88 |
| 2024 | 6.66 | 7.29 | 5.82 |
| 2023 | 3.12 | 6.96 | 0.86 |
| 2022 | 6.53 | 7.1 | 5.79 |
| 2021 | 6.41 | 7.21 | 5.43 |
| 2020 | 7.72 | 8.9 | 6.43 |
| 2019 | 9.66 | 10.48 | 8.45 |
| 2018 | 9.87 | 11 | 9.07 |
| 2017 | 11.63 | 12.73 | 10.75 |
| 2016 | 11.94 | 13.89 | 10.76 |
| 2015 | 13.73 | 20.25 | 9.77 |
| 2014 | 9.92 | 11.87 | 8.41 |
| 2013 | 11.5 | 15.31 | 9.24 |
| 2012 | 9.96 | 12.03 | 8.4 |
| 2011 | 19.38 | 30.82 | 9.76 |
| 2010 | 28.9 | 39.36 | 22.33 |
| 2009 | 22.84 | 36.05 | 8.93 |
| 2008 | 19.35 | 45.12 | 7.11 |
| 2007 | 43.79 | 56.2 | 29.34 |
| 2006 | 22.05 | 33.11 | 15.72 |
| 2005 | 5.27 | 18.56 | 1.01 |
| 2004 | 4.1 | 5.6 | 3.05 |
| 2003 | 8.31 | 10.94 | 4.5 |
| 2002 | 145.58 | 255.35 | 35.48 |
| 2001 | 11.34 | 20.19 | 3.46 |
| 2000 | 3.4 | 6.76 | 1.31 |
| 1999 | 0.4 | 0.76 | 0.19 |
| 1998 | 0.35 | 0.49 | 0.24 |
| 1997 | 0.59 | 0.85 | 0.31 |