| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.6 | 0.71 | 0.53 |
| 2024 | 0.57 | 0.81 | 0.46 |
| 2023 | 0.68 | 0.8 | 0.61 |
| 2022 | 0.76 | 1 | 0.62 |
| 2021 | 0.66 | 0.85 | 0.59 |
| 2020 | 0.65 | 0.83 | 0.54 |
| 2019 | 0.78 | 1.21 | 0.61 |
| 2018 | 1.08 | 1.66 | 0.6 |
| 2017 | 1.6 | 2.2 | 1.27 |
| 2016 | 2.58 | 4.21 | 1.87 |
| 2015 | 3.83 | 6.19 | 2.13 |
| 2014 | 3.25 | 4.64 | 2.71 |
| 2013 | 2.25 | 3.07 | 1.87 |
| 2012 | 2.46 | 3.68 | 1.91 |
| 2011 | 3.67 | 4.88 | 2.53 |
| 2010 | 24.66 | 105.15 | 3.19 |
| 2009 | 33.58 | 79.77 | 8.19 |
| 2008 | 8.98 | 12.49 | 4.63 |
| 2007 | 8.01 | 12.35 | 2.01 |
| 2006 | 1.92 | 2.9 | 1.31 |
| 2005 | 1.74 | 2.51 | 1.17 |
| 2004 | 2.86 | 3.65 | 1.7 |
| 2003 | 2.56 | 3.31 | 2.04 |
| 2002 | 4.59 | 5.17 | 3.2 |
| 2001 | 5.81 | 6.86 | 4.17 |
| 2000 | 5.3 | 7.06 | 3.42 |
| 1999 | 3.62 | 4.56 | 2.95 |
| 1998 | 3.57 | 4.77 | 2.7 |
| 1997 | 3.96 | 6.68 | 2.7 |