| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.68 | 0.76 | 0.59 |
| 2024 | 0.88 | 1.12 | 0.69 |
| 2023 | 0.9 | 1.1 | 0.56 |
| 2022 | 1.16 | 1.56 | 0.89 |
| 2021 | 0.79 | 1.42 | 0.49 |
| 2020 | 0.57 | 0.7 | 0.5 |
| 2019 | 0.77 | 0.99 | 0.64 |
| 2018 | 0.88 | 1.19 | 0.73 |
| 2017 | 1.05 | 1.3 | 0.89 |
| 2016 | 0.92 | 1.19 | 0.77 |
| 2015 | 1.12 | 1.76 | 0.77 |
| 2014 | 1.01 | 1.29 | 0.86 |
| 2013 | 1.82 | 2.87 | 1.23 |
| 2012 | 2.78 | 3.62 | 2.02 |
| 2011 | 3.43 | 4.53 | 2.81 |
| 2010 | 3.73 | 5.32 | 2.47 |
| 2009 | 3.99 | 5.41 | 1.97 |
| 2008 | 4.6 | 8.82 | 1.67 |
| 2007 | 5.64 | 9.7 | 3.5 |
| 2006 | 2.74 | 4.11 | 2.32 |
| 2005 | 2.8 | 3.68 | 1.99 |
| 2004 | 4 | 5.18 | 3.17 |
| 2003 | 3.4 | 4.15 | 2.93 |
| 2002 | 3.89 | 4.29 | 3.34 |
| 2001 | 4.81 | 5.99 | 3.49 |
| 2000 | 7.16 | 10.33 | 4.59 |
| 1999 | 3.82 | 6.23 | 2.12 |