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

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          7        0.07        0.07
         30 |          2        0.02        0.09
         42 |          1        0.01        0.10
         45 |          1        0.01        0.11
         46 |          1        0.01        0.12
         47 |          1        0.01        0.13
         48 |          3        0.03        0.16
         49 |          2        0.02        0.18
         50 |          3        0.03        0.21
         51 |          3        0.03        0.24
         52 |          3        0.03        0.27
         53 |         10        0.10        0.37
         54 |          9        0.09        0.46
         55 |         13        0.13        0.59
         56 |         20        0.20        0.79
         57 |         19        0.19        0.98
         58 |         16        0.16        1.14
         59 |         29        0.29        1.43
         60 |         25        0.25        1.68
         61 |         31        0.31        1.99
         62 |         47        0.47        2.46
         63 |        101        1.01        3.47
         64 |        119        1.19        4.66
         65 |        188        1.88        6.54
         66 |        219        2.19        8.73
         67 |        234        2.34       11.07
         68 |        338        3.38       14.45
         69 |        400        4.00       18.45
         70 |        431        4.31       22.76
         71 |        482        4.82       27.58
         72 |        622        6.22       33.80
         73 |        728        7.28       41.08
         74 |        709        7.09       48.17
         75 |        507        5.07       53.24
         76 |        718        7.18       60.42
         77 |        736        7.36       67.78
         78 |        895        8.95       76.73
         79 |        973        9.73       86.46
         80 |        420        4.20       90.66
         81 |         15        0.15       90.81
         99 |         54        0.54       91.35
          . |        865        8.65      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016