| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 6.97 | 7.22 | 6.78 |
| 2025 | 9.12 | 12.24 | 6.71 |
| 2024 | 8.16 | 12.96 | 3.27 |
| 2023 | 1.67 | 3.76 | 0.43 |
| 2022 | 4.01 | 6.67 | 2.88 |
| 2021 | 6.86 | 9.1 | 5.56 |
| 2020 | 6.41 | 7.54 | 5.56 |
| 2019 | 9.53 | 13.11 | 6.85 |
| 2018 | 12.57 | 14.91 | 10.51 |
| 2017 | 16.84 | 20.65 | 14.6 |
| 2016 | 22.94 | 26.36 | 19.61 |
| 2015 | 24.36 | 32.13 | 18.09 |
| 2014 | 15.06 | 20.99 | 13.03 |
| 2013 | 16.73 | 19.77 | 14.19 |
| 2012 | 10 | 16.25 | 5.28 |
| 2011 | 9.12 | 13.79 | 5.21 |
| 2010 | 15 | 24.66 | 11.27 |
| 2009 | 18.01 | 26.43 | 10.88 |
| 2008 | 28.3 | 71.56 | 8.63 |
| 2007 | 74.64 | 133.38 | 28.92 |
| 2006 | 19.75 | 30.49 | 12.24 |
| 2005 | 2.8 | 13.91 | 0.32 |
| 2004 | 0.79 | 1.23 | 0.45 |
| 2003 | 1.12 | 1.51 | 0.93 |
| 2002 | 2.03 | 2.48 | 1.32 |
| 2001 | 1.98 | 3.48 | 1.33 |
| 2000 | 1.17 | 1.86 | 0.73 |
| 1999 | 0.99 | 1.7 | 0.42 |
| 1998 | 0.71 | 1.02 | 0.41 |
| 1997 | 0.79 | 1.11 | 0.58 |