| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.7 | 2.1 | 1.4 |
| 2024 | 1.4 | 1.95 | 1.06 |
| 2023 | 1.62 | 2.17 | 0.96 |
| 2022 | 1 | 1.18 | 0.78 |
| 2021 | 1.12 | 1.41 | 0.97 |
| 2020 | 1.43 | 1.86 | 1.13 |
| 2019 | 1.61 | 2.03 | 1.27 |
| 2018 | 1.42 | 1.63 | 1.14 |
| 2017 | 1.82 | 1.99 | 1.36 |
| 2016 | 1.99 | 2.81 | 1.75 |
| 2015 | 3.48 | 5.71 | 2.01 |
| 2014 | 2.06 | 2.85 | 1.59 |
| 2013 | 1.8 | 2.28 | 1.44 |
| 2012 | 2.04 | 2.82 | 1.5 |
| 2011 | 2.72 | 3.69 | 1.78 |
| 2010 | 3.16 | 3.94 | 2.57 |
| 2009 | 2.1 | 2.53 | 1.4 |
| 2008 | 3.13 | 7.27 | 0.92 |
| 2007 | 5.26 | 7.53 | 2.07 |
| 2006 | 1.76 | 2.15 | 1.47 |
| 2005 | 2.11 | 2.97 | 1.62 |
| 2004 | 3.46 | 5.28 | 2.5 |
| 2003 | 4.24 | 5.07 | 3.47 |
| 2002 | 5.38 | 8.28 | 3.92 |
| 2001 | 8.65 | 10.79 | 6.88 |
| 2000 | 18.49 | 26.57 | 9 |
| 1999 | 12.65 | 20.48 | 6.81 |
| 1998 | 11.28 | 15.04 | 8.81 |