| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.22 | 1.88 | 0.69 |
| 2024 | 0.75 | 0.95 | 0.57 |
| 2023 | 0.98 | 1.11 | 0.84 |
| 2022 | 1.1 | 1.47 | 0.92 |
| 2021 | 1.16 | 1.48 | 0.94 |
| 2020 | 1.26 | 1.45 | 1.11 |
| 2019 | 1.39 | 1.9 | 1.09 |
| 2018 | 1.73 | 2.68 | 1.15 |
| 2017 | 3.57 | 5.03 | 2.24 |
| 2016 | 3.62 | 5.12 | 2.62 |
| 2015 | 3.68 | 6.01 | 2.08 |
| 2014 | 2.05 | 3.56 | 1.27 |
| 2013 | 1.63 | 2.14 | 1.36 |
| 2012 | 2.01 | 2.72 | 1.63 |
| 2011 | 2.72 | 3.58 | 1.76 |
| 2010 | 4.65 | 15.16 | 3.29 |
| 2009 | 6.14 | 13.65 | 2.84 |
| 2008 | 5.55 | 13.95 | 2.05 |
| 2007 | 8.09 | 14.51 | 2.12 |
| 2006 | 1.35 | 2.12 | 0.91 |
| 2005 | 0.96 | 1.26 | 0.68 |
| 2004 | 1.71 | 2.37 | 1.11 |
| 2003 | 2.11 | 2.85 | 1.66 |
| 2002 | 3.08 | 3.45 | 2.4 |
| 2001 | 4.28 | 6.13 | 2.79 |
| 2000 | 3.66 | 5.01 | 2.64 |