| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.27 | 0.3 | 0.23 |
| 2023 | 0.27 | 0.31 | 0.25 |
| 2022 | 0.27 | 0.3 | 0.24 |
| 2021 | 0.36 | 0.44 | 0.29 |
| 2020 | 0.48 | 0.57 | 0.43 |
| 2019 | 0.61 | 0.72 | 0.54 |
| 2018 | 0.73 | 0.93 | 0.6 |
| 2017 | 0.88 | 1.04 | 0.79 |
| 2016 | 1.07 | 1.18 | 1.01 |
| 2015 | 1.3 | 1.58 | 1.06 |
| 2014 | 1.07 | 1.59 | 0.92 |
| 2013 | 1.53 | 2.15 | 1.13 |
| 2012 | 1.26 | 1.46 | 1.04 |
| 2011 | 1.37 | 1.59 | 1.25 |
| 2010 | 1.88 | 3.01 | 1.34 |
| 2009 | 2.23 | 2.98 | 1.33 |
| 2008 | 2.61 | 5.19 | 1.28 |
| 2007 | 6.81 | 12.38 | 4.54 |
| 2006 | 3.1 | 5.96 | 1.91 |
| 2005 | 2.26 | 2.63 | 1.74 |
| 2004 | 3.62 | 7.59 | 2.25 |
| 2003 | 4.91 | 6.36 | 3.8 |
| 2002 | 5.22 | 5.96 | 4.01 |
| 2001 | 5.21 | 5.55 | 4.5 |