Frequencies for first 10,000 rows of mod_year variable in vehicle dataset : MODEL YEAR | Freq. Percent Cum. ------------+----------------------------------- 1920 | 1 0.01 0.01 1928 | 1 0.01 0.02 1929 | 1 0.01 0.03 1931 | 1 0.01 0.04 1935 | 1 0.01 0.05 1946 | 1 0.01 0.06 1947 | 1 0.01 0.07 1948 | 2 0.02 0.09 1949 | 1 0.01 0.10 1951 | 1 0.01 0.11 1952 | 1 0.01 0.12 1955 | 2 0.02 0.14 1957 | 1 0.01 0.15 1958 | 1 0.01 0.16 1959 | 2 0.02 0.18 1960 | 1 0.01 0.19 1961 | 1 0.01 0.20 1962 | 2 0.02 0.22 1963 | 8 0.08 0.30 1964 | 10 0.10 0.40 1965 | 12 0.12 0.52 1966 | 22 0.22 0.74 1967 | 11 0.11 0.85 1968 | 16 0.16 1.01 1969 | 29 0.29 1.30 1970 | 33 0.33 1.63 1971 | 34 0.34 1.97 1972 | 42 0.42 2.39 1973 | 49 0.49 2.88 1974 | 37 0.37 3.25 1975 | 38 0.38 3.63 1976 | 45 0.45 4.08 1977 | 80 0.80 4.88 1978 | 87 0.87 5.75 1979 | 120 1.20 6.95 1980 | 100 1.00 7.95 1981 | 129 1.29 9.24 1982 | 136 1.36 10.60 1983 | 188 1.88 12.48 1984 | 253 2.53 15.01 1985 | 359 3.59 18.60 1986 | 405 4.05 22.65 1987 | 420 4.20 26.85 1988 | 503 5.03 31.88 1989 | 603 6.03 37.91 1990 | 505 5.05 42.96 1991 | 513 5.13 48.09 1992 | 479 4.79 52.88 1993 | 574 5.74 58.62 1994 | 642 6.42 65.04 1995 | 690 6.90 71.94 1996 | 553 5.53 77.47 1997 | 639 6.39 83.86 1998 | 683 6.83 90.69 1999 | 653 6.53 97.22 2000 | 55 0.55 97.77 9999 | 223 2.23 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Apr 2016