| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.21 | 0.98 |
| 2024 | 1.12 | 1.42 | 0.92 |
| 2023 | 1.62 | 2.21 | 1.27 |
| 2022 | 1.85 | 2.74 | 1.32 |
| 2021 | 1.57 | 2.49 | 0.98 |
| 2020 | 1.16 | 1.56 | 0.87 |
| 2019 | 1.74 | 3.09 | 1.06 |
| 2018 | 3.56 | 6.38 | 1.83 |
| 2017 | 5.86 | 8.58 | 3.63 |
| 2016 | 3.52 | 5.72 | 2.1 |
| 2015 | 2.33 | 3.59 | 1.44 |
| 2014 | 1.79 | 2.06 | 1.58 |
| 2013 | 2.33 | 3.28 | 1.76 |
| 2012 | 2.28 | 3.69 | 1.52 |
| 2011 | 2.52 | 3.44 | 1.6 |
| 2010 | 3.44 | 4.97 | 2.47 |
| 2009 | 3.72 | 5.58 | 1.91 |
| 2008 | 4.79 | 9.62 | 1.44 |
| 2007 | 4.68 | 8.62 | 1.75 |
| 2006 | 1.78 | 2.24 | 1.45 |
| 2005 | 1.49 | 2 | 1.17 |
| 2004 | 2.55 | 4.48 | 1.94 |
| 2003 | 3.94 | 4.68 | 2.65 |
| 2002 | 3.61 | 4.36 | 2.36 |
| 2001 | 5.08 | 6.98 | 3.38 |