| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.92 | 2.16 | 1.54 |
| 2024 | 1.59 | 1.92 | 1.28 |
| 2023 | 1.84 | 2.08 | 1.66 |
| 2022 | 2.02 | 3.65 | 1.59 |
| 2021 | 2.79 | 3.45 | 2.28 |
| 2020 | 3.2 | 5.46 | 2.07 |
| 2019 | 1.69 | 3.08 | 1.19 |
| 2018 | 1.39 | 1.69 | 1.21 |
| 2017 | 1.81 | 2.15 | 1.51 |
| 2016 | 2.04 | 2.52 | 1.87 |
| 2015 | 2.53 | 3.92 | 1.68 |
| 2014 | 1.91 | 2.4 | 1.58 |
| 2013 | 3.46 | 9.1 | 1.5 |
| 2012 | 6.35 | 8.21 | 4.72 |
| 2011 | 11.76 | 16.61 | 6.35 |
| 2010 | 14.59 | 20.19 | 10.03 |
| 2009 | 8.32 | 19.86 | 4.69 |
| 2008 | 5.88 | 9.21 | 3.15 |
| 2007 | 5.48 | 8.93 | 1.98 |
| 2006 | 1.61 | 2.19 | 1.17 |
| 2005 | 1.16 | 1.43 | 0.83 |
| 2004 | 2.49 | 3.71 | 1.21 |
| 2003 | 2.95 | 3.72 | 2.29 |
| 2002 | 2.78 | 3.25 | 1.99 |
| 2001 | 3.14 | 3.7 | 2.54 |
| 2000 | 3.15 | 4.16 | 2.08 |
| 1999 | 2.52 | 3.54 | 2.03 |
| 1998 | 3.08 | 4.26 | 2.2 |
| 1997 | 4.44 | 5.51 | 3.15 |