Frequencies for pmodyear variable in parkwork dataset : Vehicle | Model Year | Freq. Percent Cum. ------------+----------------------------------- 1953 | 1 0.09 0.09 1956 | 1 0.09 0.19 1961 | 1 0.09 0.28 1966 | 1 0.09 0.38 1969 | 1 0.09 0.47 1970 | 1 0.09 0.56 1971 | 1 0.09 0.66 1972 | 1 0.09 0.75 1974 | 1 0.09 0.85 1976 | 1 0.09 0.94 1978 | 2 0.19 1.13 1979 | 3 0.28 1.41 1980 | 2 0.19 1.60 1982 | 3 0.28 1.88 1983 | 3 0.28 2.16 1984 | 3 0.28 2.44 1985 | 1 0.09 2.54 1986 | 10 0.94 3.48 1987 | 11 1.03 4.51 1988 | 7 0.66 5.17 1989 | 14 1.32 6.48 1990 | 8 0.75 7.24 1991 | 12 1.13 8.36 1992 | 16 1.50 9.87 1993 | 19 1.79 11.65 1994 | 37 3.48 15.13 1995 | 47 4.42 19.55 1996 | 40 3.76 23.31 1997 | 52 4.89 28.20 1998 | 48 4.51 32.71 1999 | 59 5.55 38.25 2000 | 73 6.86 45.11 2001 | 56 5.26 50.38 2002 | 60 5.64 56.02 2003 | 74 6.95 62.97 2004 | 54 5.08 68.05 2005 | 64 6.02 74.06 2006 | 62 5.83 79.89 2007 | 64 6.02 85.90 2008 | 54 5.08 90.98 2009 | 33 3.10 94.08 2010 | 34 3.20 97.27 2011 | 6 0.56 97.84 9999 | 23 2.16 100.00 ------------+----------------------------------- Total | 1,064 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016