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

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         48 |          2        0.02        0.02
         51 |          1        0.01        0.03
         52 |          1        0.01        0.04
         53 |          2        0.02        0.06
         54 |          2        0.02        0.08
         55 |          7        0.07        0.15
         56 |          5        0.05        0.20
         57 |          3        0.03        0.23
         58 |          7        0.07        0.30
         59 |          2        0.02        0.32
         60 |          3        0.03        0.35
         61 |         10        0.10        0.45
         62 |         15        0.15        0.60
         63 |         26        0.26        0.86
         64 |         35        0.35        1.21
         65 |         61        0.61        1.82
         66 |         76        0.76        2.58
         67 |         88        0.88        3.46
         68 |         80        0.80        4.26
         69 |        135        1.35        5.61
         70 |        144        1.44        7.05
         71 |        149        1.49        8.54
         72 |        192        1.92       10.46
         73 |        286        2.86       13.32
         74 |        334        3.34       16.66
         75 |        253        2.53       19.19
         76 |        350        3.50       22.69
         77 |        483        4.83       27.52
         78 |        525        5.25       32.77
         79 |        615        6.15       38.92
         80 |        489        4.89       43.81
         81 |        503        5.03       48.84
         82 |        494        4.94       53.78
         83 |        475        4.75       58.53
         84 |        676        6.76       65.29
         85 |        771        7.71       73.00
         86 |        859        8.59       81.59
         87 |        858        8.58       90.17
         88 |        666        6.66       96.83
         89 |         21        0.21       97.04
         99 |        296        2.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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