| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.48 | 0.54 | 0.44 |
| 2024 | 0.43 | 0.59 | 0.35 |
| 2023 | 0.51 | 0.64 | 0.42 |
| 2022 | 0.74 | 0.99 | 0.56 |
| 2021 | 0.88 | 1.28 | 0.73 |
| 2020 | 0.64 | 1.14 | 0.53 |
| 2019 | 0.73 | 0.91 | 0.6 |
| 2018 | 0.81 | 0.94 | 0.7 |
| 2017 | 1.19 | 1.64 | 0.9 |
| 2016 | 1.07 | 1.54 | 0.94 |
| 2015 | 1.46 | 2.47 | 0.91 |
| 2014 | 0.8 | 1.15 | 0.64 |
| 2013 | 1.24 | 2.02 | 0.86 |
| 2012 | 1.12 | 1.38 | 0.93 |
| 2011 | 1.58 | 1.87 | 1.12 |
| 2010 | 1.52 | 2.11 | 1.17 |
| 2009 | 1.7 | 2.55 | 1.04 |
| 2008 | 2.25 | 5.01 | 0.86 |
| 2007 | 4.18 | 6.19 | 1.93 |
| 2006 | 1.81 | 2.27 | 1.41 |
| 2005 | 1.72 | 2.08 | 1.19 |
| 2004 | 2.13 | 3.62 | 1.29 |