| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.4 | 1.78 | 1.11 |
| 2024 | 1.16 | 1.37 | 0.93 |
| 2023 | 1.58 | 1.99 | 1.28 |
| 2022 | 2 | 2.8 | 1.62 |
| 2021 | 2.3 | 2.68 | 1.91 |
| 2020 | 2.27 | 3.24 | 1.28 |
| 2019 | 1.49 | 1.92 | 1.13 |
| 2018 | 1.93 | 2.46 | 1.19 |
| 2017 | 1.87 | 2.34 | 1.5 |
| 2016 | 1.79 | 2.05 | 1.42 |
| 2015 | 2.43 | 3.73 | 1.45 |
| 2014 | 2.59 | 3.4 | 2.2 |
| 2013 | 2.77 | 3.38 | 2.23 |
| 2012 | 2.96 | 3.88 | 2.42 |
| 2011 | 5.25 | 7.62 | 3.88 |
| 2010 | 6.49 | 8.61 | 4.61 |
| 2009 | 5.23 | 7.43 | 4.21 |
| 2008 | 5.43 | 8.65 | 3.18 |
| 2007 | 4.4 | 6.27 | 1.99 |
| 2006 | 2.17 | 2.92 | 1.84 |
| 2005 | 3.36 | 4.51 | 2.27 |
| 2004 | 4.78 | 5.64 | 2.82 |
| 2003 | 3.7 | 4.29 | 3.15 |
| 2002 | 4.29 | 5.14 | 3.6 |
| 2001 | 6.54 | 8.21 | 4.8 |