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

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         16 |          1        0.01        0.01
         17 |          1        0.01        0.02
         31 |          2        0.02        0.04
         33 |          1        0.01        0.05
         37 |          1        0.01        0.06
         38 |          1        0.01        0.07
         40 |          1        0.01        0.08
         46 |          2        0.02        0.10
         47 |          2        0.02        0.12
         48 |          4        0.04        0.16
         49 |         12        0.12        0.28
         50 |         10        0.10        0.38
         51 |         13        0.13        0.51
         52 |         10        0.10        0.61
         53 |         12        0.12        0.73
         54 |         18        0.18        0.91
         55 |         31        0.31        1.22
         56 |         32        0.32        1.54
         57 |         43        0.43        1.97
         58 |         30        0.30        2.27
         59 |         43        0.43        2.70
         60 |         67        0.67        3.37
         61 |         77        0.77        4.14
         62 |        131        1.31        5.45
         63 |        180        1.80        7.25
         64 |        285        2.85       10.10
         65 |        353        3.53       13.63
         66 |        386        3.86       17.49
         67 |        458        4.58       22.07
         68 |        548        5.48       27.55
         69 |        641        6.41       33.96
         70 |        667        6.67       40.63
         71 |        653        6.53       47.16
         72 |        840        8.40       55.56
         73 |        925        9.25       64.81
         74 |        911        9.11       73.92
         75 |        714        7.14       81.06
         76 |        933        9.33       90.39
         77 |        772        7.72       98.11
         78 |         32        0.32       98.43
         79 |          1        0.01       98.44
         80 |          3        0.03       98.47
         99 |        153        1.53      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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