| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.1 | 0.11 | 0.09 |
| 2024 | 0.09 | 0.12 | 0.07 |
| 2023 | 0.1 | 0.16 | 0.08 |
| 2022 | 0.1 | 0.14 | 0.07 |
| 2021 | 0.76 | 2.22 | 0.07 |
| 2020 | 0.49 | 2.01 | 0.35 |
| 2019 | 0.63 | 1.26 | 0.38 |
| 2018 | 0.74 | 1 | 0.58 |
| 2017 | 1.06 | 1.58 | 0.82 |
| 2016 | 1.21 | 1.81 | 0.77 |
| 2015 | 1.04 | 1.89 | 0.68 |
| 2014 | 0.72 | 0.9 | 0.6 |
| 2013 | 0.7 | 0.8 | 0.63 |
| 2012 | 0.74 | 0.86 | 0.61 |
| 2011 | 1.17 | 1.6 | 0.68 |
| 2010 | 1.19 | 1.59 | 0.91 |
| 2009 | 7.21 | 32.56 | 1.3 |
| 2008 | 20.86 | 22.49 | 19.3 |
| 2007 | 9.44 | 12.87 | 6.41 |
| 2006 | 4.24 | 7.14 | 1.8 |
| 2005 | 1.18 | 2.24 | 0.42 |
| 2004 | 1.11 | 2.3 | 0.61 |