| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.07 | 1.33 | 0.99 |
| 2024 | 1.12 | 1.37 | 0.87 |
| 2023 | 1.72 | 2.15 | 1.27 |
| 2022 | 1.8 | 2.55 | 1.42 |
| 2021 | 1.55 | 2.57 | 1 |
| 2020 | 1.11 | 1.48 | 0.94 |
| 2019 | 1.54 | 2.39 | 0.79 |
| 2018 | 0.97 | 1.34 | 0.76 |
| 2017 | 2.12 | 3.68 | 1.23 |
| 2016 | 2.62 | 3.27 | 1.76 |
| 2015 | 3.22 | 4.02 | 1.89 |
| 2014 | 9.19 | 14.96 | 1.63 |
| 2013 | 6.17 | 7.66 | 5.07 |
| 2012 | 5.77 | 7.36 | 3.77 |
| 2011 | 10.18 | 14.54 | 5.83 |
| 2010 | 12.78 | 16.22 | 9.36 |
| 2009 | 12.85 | 15.89 | 7.47 |
| 2008 | 15.87 | 32.53 | 5.13 |
| 2007 | 14.45 | 25.73 | 4.16 |
| 2006 | 4.68 | 5.64 | 3.68 |
| 2005 | 2.19 | 3.95 | 0.58 |
| 2004 | 1.43 | 1.97 | 0.8 |
| 2003 | 1.81 | 2.31 | 1.38 |
| 2002 | 2.85 | 3.1 | 2.33 |
| 2001 | 3.77 | 4.52 | 2.52 |
| 2000 | 6.29 | 8.33 | 4.91 |
| 1999 | 4.06 | 5.2 | 2.37 |