Frequencies for first 10,000 rows of mod_year variable in person dataset :

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         46 |          2        0.02        0.02
         47 |          2        0.02        0.04
         48 |          4        0.04        0.08
         49 |          2        0.02        0.10
         50 |          2        0.02        0.12
         51 |          4        0.04        0.16
         52 |          4        0.04        0.20
         53 |          2        0.02        0.22
         54 |          2        0.02        0.24
         55 |          9        0.09        0.33
         56 |         15        0.15        0.48
         57 |          6        0.06        0.54
         58 |         30        0.30        0.84
         59 |         14        0.14        0.98
         60 |         30        0.30        1.28
         61 |         29        0.29        1.57
         62 |         44        0.44        2.01
         63 |         60        0.60        2.61
         64 |        131        1.31        3.92
         65 |        180        1.80        5.72
         66 |        154        1.54        7.26
         67 |        173        1.73        8.99
         68 |        234        2.34       11.33
         69 |        290        2.90       14.23
         70 |        330        3.30       17.53
         71 |        349        3.49       21.02
         72 |        498        4.98       26.00
         73 |        603        6.03       32.03
         74 |        594        5.94       37.97
         75 |        477        4.77       42.74
         76 |        541        5.41       48.15
         77 |        667        6.67       54.82
         78 |        788        7.88       62.70
         79 |        889        8.89       71.59
         80 |        683        6.83       78.42
         81 |        752        7.52       85.94
         82 |        377        3.77       89.71
         83 |          5        0.05       89.76
         99 |        172        1.72       91.48
          . |        852        8.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016