| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.86 | 2.04 | 1.66 |
| 2024 | 1.52 | 2.29 | 1.07 |
| 2023 | 1.75 | 2.09 | 1.51 |
| 2022 | 2.06 | 3.11 | 1.51 |
| 2021 | 3.63 | 6.27 | 2.69 |
| 2020 | 3.62 | 5.57 | 2.26 |
| 2019 | 2.41 | 3.35 | 2.02 |
| 2018 | 2.38 | 3.16 | 1.71 |
| 2017 | 3.38 | 5.09 | 2.54 |
| 2016 | 4.15 | 5.24 | 3.62 |
| 2015 | 9.43 | 17.91 | 5.29 |
| 2014 | 3.96 | 7.48 | 1.92 |
| 2013 | 1.94 | 2.23 | 1.57 |
| 2012 | 2 | 2.48 | 1.48 |
| 2011 | 2.71 | 3.65 | 1.56 |
| 2010 | 2.75 | 3.98 | 2.1 |
| 2009 | 1.91 | 2.69 | 1 |
| 2008 | 2.71 | 7.81 | 0.75 |
| 2007 | 5.58 | 9.01 | 2.16 |
| 2006 | 1.81 | 3.24 | 0.95 |
| 2005 | 1.2 | 1.4 | 0.92 |
| 2004 | 1.59 | 2.25 | 1.19 |
| 2003 | 1.93 | 2.45 | 1.52 |
| 2002 | 3 | 3.4 | 2.4 |
| 2001 | 4.28 | 5.18 | 2.96 |
| 2000 | 5.35 | 7.65 | 4.49 |
| 1999 | 4.13 | 5.64 | 2.28 |
| 1998 | 3.15 | 4.97 | 1.9 |
| 1997 | 3.61 | 5.52 | 2.6 |