| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.82 | 1.97 | 1.66 |
| 2024 | 1.91 | 2.54 | 1.48 |
| 2023 | 2.66 | 3.13 | 2.21 |
| 2022 | 2.2 | 3.03 | 1.45 |
| 2021 | 3.34 | 4.49 | 2.6 |
| 2020 | 3.63 | 5.64 | 2.4 |
| 2019 | 1.64 | 3.27 | 1.23 |
| 2018 | 1.39 | 1.89 | 1.11 |
| 2017 | 2.14 | 2.63 | 1.65 |
| 2016 | 2.59 | 4.2 | 2.26 |
| 2015 | 3.9 | 7 | 2.43 |
| 2014 | 2.26 | 3.83 | 1.74 |
| 2013 | 2.86 | 4.27 | 2.28 |
| 2012 | 3.95 | 5.88 | 2.61 |
| 2011 | 7.45 | 12.47 | 3.9 |
| 2010 | 13.95 | 25.67 | 9.38 |
| 2009 | 27.27 | 106.51 | 10.71 |
| 2008 | 15.22 | 57.19 | 4.36 |
| 2007 | 3.96 | 6.4 | 0.89 |
| 2006 | 0.89 | 1.04 | 0.66 |
| 2005 | 1.04 | 1.41 | 0.83 |
| 2004 | 1.85 | 2.48 | 1.38 |
| 2003 | 2.5 | 3.18 | 1.93 |
| 2002 | 3.18 | 3.54 | 2.75 |
| 2001 | 4.11 | 4.81 | 2.96 |