Frequencies for vin_bt variable in vehicle dataset :

     vin_bt |      Freq.     Percent        Cum.
------------+-----------------------------------
            |          2        0.42        0.42
         2D |         27        5.72        6.14
         2H |         26        5.51       11.65
         2W |          1        0.21       11.86
         3C |          1        0.21       12.08
         4C |          7        1.48       13.56
         4D |        114       24.15       37.71
         4H |          9        1.91       39.62
         4P |          1        0.21       39.83
         4W |          8        1.69       41.53
         99 |         82       17.37       58.90
         BU |          2        0.42       59.32
         CB |          1        0.21       59.53
         CC |          6        1.27       60.81
         CG |          2        0.42       61.23
         CP |         16        3.39       64.62
         CV |          2        0.42       65.04
         CW |          7        1.48       66.53
         DP |          1        0.21       66.74
         DS |          4        0.85       67.58
         EC |          1        0.21       67.80
         ES |          2        0.42       68.22
         IC |          1        0.21       68.43
         IE |          1        0.21       68.64
         LB |          2        0.42       69.07
         MY |          1        0.21       69.28
         PC |          7        1.48       70.76
         PK |         15        3.18       73.94
         PS |          3        0.64       74.58
         RS |         28        5.93       80.51
         SV |         12        2.54       83.05
         SW |         12        2.54       85.59
         TM |          3        0.64       86.23
         UT |         64       13.56       99.79
         YY |          1        0.21      100.00
------------+-----------------------------------
      Total |        472      100.00

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