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

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         42 |          3        0.03        0.03
         48 |          1        0.01        0.04
         49 |          2        0.02        0.06
         51 |          1        0.01        0.07
         52 |          3        0.03        0.10
         54 |          1        0.01        0.11
         55 |          4        0.04        0.15
         56 |          6        0.06        0.21
         57 |          1        0.01        0.22
         58 |          2        0.02        0.24
         59 |          2        0.02        0.26
         60 |          9        0.09        0.35
         61 |         10        0.10        0.45
         62 |         13        0.13        0.58
         63 |         19        0.19        0.77
         64 |         30        0.30        1.07
         65 |         46        0.46        1.53
         66 |         50        0.50        2.03
         67 |         75        0.75        2.78
         68 |        125        1.25        4.03
         69 |        120        1.20        5.23
         70 |        147        1.47        6.70
         71 |        175        1.75        8.45
         72 |        303        3.03       11.48
         73 |        283        2.83       14.31
         74 |        340        3.40       17.71
         75 |        267        2.67       20.38
         76 |        405        4.05       24.43
         77 |        490        4.90       29.33
         78 |        677        6.77       36.10
         79 |        622        6.22       42.32
         80 |        470        4.70       47.02
         81 |        469        4.69       51.71
         82 |        461        4.61       56.32
         83 |        474        4.74       61.06
         84 |        708        7.08       68.14
         85 |        755        7.55       75.69
         86 |        921        9.21       84.90
         87 |        544        5.44       90.34
         88 |         29        0.29       90.63
         99 |        161        1.61       92.24
          . |        776        7.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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