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

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         48 |          3        0.03        0.03
         52 |          7        0.07        0.10
         53 |          2        0.02        0.12
         54 |          1        0.01        0.13
         55 |          7        0.07        0.20
         56 |          3        0.03        0.23
         57 |          3        0.03        0.26
         58 |          2        0.02        0.28
         59 |          2        0.02        0.30
         60 |          2        0.02        0.32
         61 |          7        0.07        0.39
         62 |          6        0.06        0.45
         63 |         32        0.32        0.77
         64 |         14        0.14        0.91
         65 |         54        0.54        1.45
         66 |         58        0.58        2.03
         67 |         67        0.67        2.70
         68 |         83        0.83        3.53
         69 |        110        1.10        4.63
         70 |        140        1.40        6.03
         71 |        113        1.13        7.16
         72 |        144        1.44        8.60
         73 |        248        2.48       11.08
         74 |        310        3.10       14.18
         75 |        206        2.06       16.24
         76 |        316        3.16       19.40
         77 |        491        4.91       24.31
         78 |        513        5.13       29.44
         79 |        615        6.15       35.59
         80 |        449        4.49       40.08
         81 |        459        4.59       44.67
         82 |        499        4.99       49.66
         83 |        492        4.92       54.58
         84 |        607        6.07       60.65
         85 |        809        8.09       68.74
         86 |        846        8.46       77.20
         87 |        800        8.00       85.20
         88 |        501        5.01       90.21
         89 |         17        0.17       90.38
         99 |        141        1.41       91.79
          . |        821        8.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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