| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.31 | 1.45 | 1.26 |
| 2024 | 1.42 | 1.66 | 1.23 |
| 2023 | 1.92 | 2.24 | 1.51 |
| 2022 | 1.55 | 2.09 | 0.87 |
| 2021 | 1.54 | 1.98 | 1.1 |
| 2020 | 1.02 | 1.56 | 0.75 |
| 2019 | 0.91 | 1.25 | 0.67 |
| 2018 | 0.78 | 1.02 | 0.57 |
| 2017 | 1.08 | 1.29 | 0.96 |
| 2016 | 1 | 1.21 | 0.83 |
| 2015 | 1.36 | 2.19 | 0.96 |
| 2014 | 1.03 | 1.25 | 0.9 |
| 2013 | 1.12 | 1.47 | 0.93 |
| 2012 | 1.54 | 2.2 | 1.03 |
| 2011 | 2.3 | 3.33 | 1.36 |
| 2010 | 4.14 | 5.81 | 3.04 |
| 2009 | 3.69 | 5.27 | 1.43 |
| 2008 | 3.17 | 6.54 | 0.94 |
| 2007 | 5.65 | 8.69 | 1.93 |
| 2006 | 1.42 | 2.15 | 0.77 |
| 2005 | 1.09 | 1.87 | 0.74 |
| 2004 | 2.4 | 3.97 | 1.47 |
| 2003 | 3.07 | 4.14 | 1.9 |
| 2002 | 2.65 | 3.12 | 2.22 |
| 2001 | 3.95 | 5.01 | 2.57 |
| 2000 | 6.8 | 9.6 | 5.17 |
| 1999 | 6.41 | 8.74 | 4.23 |