
| 2024 | 0.47 | 2.12 | 18.34 | 22% |
| 2023 | 0.49 | 2.03 | 17.65 | 24.2% |
| 2022 | 0.52 | 1.85 | 16.25 | 28.2% |
| 2021 | 0.54 | 1.78 | 15.77 | 30.3% |
| 2020 | 0.53 | 1.68 | 14.95 | 31.5% |
| 2019 | 0.59 | 1.86 | 16.79 | 31.7% |
| 2018 | 0.55 | 1.81 | 16.51 | 30.2% |
| 2017 | 0.5 | 1.76 | 16.29 | 28.6% |
| 2016 | 0.5 | 1.51 | 14.12 | 32.9% |
| 2015 | 0.39 | 1.49 | 14.11 | 26.5% |
| 2014 | 0.42 | 1.26 | 12.11 | 33.8% |
| 2013 | 0.44 | 1.26 | 12.39 | 34.5% |
| 2012 | 0.4 | 1.17 | 11.71 | 34.5% |
| 2011 | 0.41 | 1.12 | 11.36 | 37% |
| 2010 | 0.39 | 1.1 | 11.44 | 35.2% |
| 2009 | 0.37 | 1.03 | 10.94 | 35.6% |
| 2008 | 0.31 | 1.08 | 11.66 | 28.9% |
| 2007 | 0.29 | 1.02 | 11.23 | 27.9% |
| 2006 | 0.24 | 0.99 | 11 | 24.5% |
| 2005 | 0.24 | 1 | 11.41 | 24.4% |
| 2004 | 0.23 | 1.05 | 12.17 | 22.3% |
| 2003 | 0.22 | 1.01 | 11.89 | 21.9% |
| 2002 | 0.19 | 1 | 11.98 | 19.5% |
| 2001 | 0.12 | 0.97 | 11.92 | 12.2% |
| 2000 | 0.1 | 1 | 12.58 | 9.8% |
| 1999 | 0.09 | 0.98 | 12.59 | 9.3% |
| 1998 | 0.08 | 0.98 | 12.87 | 7.7% |
| 1997 | 0.07 | 0.93 | 12.63 | 7.6% |
| 1996 | 0.07 | 0.86 | 11.95 | 8.5% |
| 1995 | 0.08 | 0.81 | 11.42 | 9.7% |
| 1994 | 0.08 | 0.75 | 10.8 | 11.3% |
| 1993 | 0.09 | 0.7 | 10.42 | 13.2% |
| 1992 | 0.09 | 0.65 | 9.8 | 13.6% |
| 1991 | 0.07 | 0.6 | 9.32 | 12.2% |
| 1990 | 0.08 | 0.59 | 9.4 | 13.1% |
| 1989 | 0.08 | 0.58 | 9.48 | 13.8% |
| 1988 | 0.08 | 0.49 | 8.28 | 16.1% |
| 1987 | 0.07 | 0.47 | 8.01 | 15% |
| 1986 | 0.08 | 0.4 | 7.09 | 19.3% |
| 1985 | 0.08 | 0.39 | 7.03 | 20.6% |
| 1984 | 0.08 | 0.42 | 7.79 | 19.8% |
| 1983 | 0.05 | 0.47 | 8.91 | 9.8% |
| 1982 | 0.04 | 0.48 | 9.47 | 7.6% |
| 1981 | 0.03 | 0.48 | 9.79 | 6% |
| 1980 | 0.03 | 0.51 | 10.6 | 5.1% |