| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.54 | 0.62 | 0.45 |
| 2024 | 0.47 | 0.74 | 0.34 |
| 2023 | 0.57 | 0.68 | 0.49 |
| 2022 | 0.7 | 0.97 | 0.55 |
| 2021 | 0.69 | 0.95 | 0.59 |
| 2020 | 0.72 | 0.86 | 0.64 |
| 2019 | 0.85 | 1.02 | 0.73 |
| 2018 | 0.98 | 1.43 | 0.67 |
| 2017 | 1.47 | 1.69 | 1.28 |
| 2016 | 1.47 | 1.76 | 1.27 |
| 2015 | 2.16 | 4.04 | 1.35 |
| 2014 | 1.52 | 1.9 | 1.18 |
| 2013 | 2.11 | 2.55 | 1.62 |
| 2012 | 1.86 | 2.48 | 1.48 |
| 2011 | 2.6 | 3.83 | 1.51 |
| 2010 | 4.04 | 5.55 | 2.89 |
| 2009 | 4.61 | 7.06 | 1.54 |
| 2008 | 5.3 | 12.53 | 1.37 |
| 2007 | 10.55 | 19.18 | 4.47 |
| 2006 | 3.52 | 5.05 | 2.9 |
| 2005 | 3.33 | 4.19 | 2.46 |
| 2004 | 5.83 | 9.23 | 3.6 |
| 2003 | 5.66 | 6.13 | 4.98 |
| 2002 | 5.18 | 5.78 | 3.84 |
| 2001 | 5.73 | 6.78 | 4.18 |
| 2000 | 8.77 | 11.67 | 6.12 |
| 1999 | 6.73 | 9.02 | 5.15 |
| 1998 | 5.85 | 7.88 | 4.34 |