| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.12 | 1.78 | 0.69 |
| 2025 | 0.54 | 0.89 | 0.4 |
| 2024 | 0.4 | 0.53 | 0.29 |
| 2023 | 0.47 | 0.74 | 0.37 |
| 2022 | 0.42 | 0.6 | 0.33 |
| 2021 | 0.56 | 0.93 | 0.38 |
| 2020 | 0.96 | 1.52 | 0.55 |
| 2019 | 1.32 | 1.95 | 1.08 |
| 2018 | 1.61 | 2.4 | 1.11 |
| 2017 | 2.79 | 3.82 | 2.03 |
| 2016 | 3.61 | 4.33 | 3.06 |
| 2015 | 4.01 | 6.04 | 2.56 |
| 2014 | 2.29 | 3.62 | 1.65 |
| 2013 | 2.18 | 3.24 | 1.67 |
| 2012 | 2.07 | 3.03 | 1.6 |
| 2011 | 3.05 | 4.13 | 1.78 |
| 2010 | 3.58 | 4.58 | 2.7 |
| 2009 | 3.71 | 6.64 | 1.97 |
| 2008 | 3.76 | 10.27 | 1.22 |
| 2007 | 5.71 | 10.66 | 1.87 |
| 2006 | 2.13 | 3.16 | 1.77 |
| 2005 | 2.37 | 3.83 | 1.66 |
| 2004 | 3.49 | 4.74 | 2.8 |
| 2003 | 5.48 | 7.58 | 3.02 |
| 2002 | 7.81 | 9.35 | 5.65 |
| 2001 | 8.66 | 10.54 | 6.57 |
| 2000 | 9.5 | 12.72 | 5.81 |
| 1999 | 2.7 | 3.78 | 1.96 |
| 1998 | 2.63 | 3.18 | 2.1 |
| 1997 | 2.92 | 4.76 | 1.89 |