| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0.98 | 1.76 | 0.48 |
| 2023 | 1.58 | 1.83 | 1.29 |
| 2022 | 1.9 | 2.51 | 1.45 |
| 2021 | 1.37 | 2.13 | 1.08 |
| 2020 | 1.76 | 2.47 | 1.19 |
| 2019 | 1.73 | 2.16 | 1.49 |
| 2018 | 1.8 | 2.31 | 1.54 |
| 2017 | 2.83 | 3.52 | 2.1 |
| 2016 | 4.07 | 5.65 | 3.47 |
| 2015 | 6.15 | 11.04 | 3.18 |
| 2014 | 3.09 | 4.4 | 2.29 |
| 2013 | 3.32 | 4.58 | 2.51 |
| 2012 | 5.62 | 8.26 | 3.69 |
| 2011 | 9.08 | 14.19 | 5.65 |
| 2010 | 9.55 | 13.7 | 6.86 |
| 2009 | 7.81 | 12.91 | 5.08 |
| 2008 | 6.63 | 10.39 | 2.48 |
| 2007 | 5.11 | 7.95 | 2.45 |
| 2006 | 2.51 | 3.3 | 1.81 |
| 2005 | 2.14 | 3.1 | 1.5 |
| 2004 | 3.73 | 5.64 | 2.73 |
| 2003 | 4.91 | 5.75 | 3.95 |
| 2002 | 5.17 | 6.18 | 3.82 |
| 2001 | 6.4 | 8.64 | 4.13 |
| 2000 | 10.24 | 13.83 | 6.14 |
| 1999 | 6.15 | 7.42 | 4.14 |