Frequencies for pmodyear variable in parkwork dataset : vehicle | model year | Freq. Percent Cum. ------------+----------------------------------- 1965 | 1 0.09 0.09 1968 | 1 0.09 0.18 1972 | 1 0.09 0.26 1973 | 1 0.09 0.35 1975 | 1 0.09 0.44 1978 | 2 0.18 0.62 1979 | 1 0.09 0.71 1982 | 1 0.09 0.79 1983 | 2 0.18 0.97 1984 | 1 0.09 1.06 1985 | 4 0.35 1.41 1986 | 3 0.26 1.68 1987 | 3 0.26 1.94 1988 | 4 0.35 2.29 1989 | 6 0.53 2.82 1990 | 4 0.35 3.18 1991 | 7 0.62 3.80 1992 | 5 0.44 4.24 1993 | 13 1.15 5.38 1994 | 8 0.71 6.09 1995 | 18 1.59 7.68 1996 | 18 1.59 9.27 1997 | 26 2.29 11.56 1998 | 40 3.53 15.09 1999 | 48 4.24 19.33 2000 | 52 4.59 23.92 2001 | 59 5.21 29.13 2002 | 52 4.59 33.72 2003 | 66 5.83 39.54 2004 | 73 6.44 45.98 2005 | 71 6.27 52.25 2006 | 77 6.80 59.05 2007 | 72 6.35 65.40 2008 | 37 3.27 68.67 2009 | 36 3.18 71.84 2010 | 42 3.71 75.55 2011 | 38 3.35 78.91 2012 | 42 3.71 82.61 2013 | 58 5.12 87.73 2014 | 46 4.06 91.79 2015 | 56 4.94 96.73 2016 | 15 1.32 98.06 9999 | 22 1.94 100.00 ------------+----------------------------------- Total | 1,133 100.00 by Jean Roth , jroth@nber.org , 22 Oct 2016