Frequencies for vin_bt variable in vehnit dataset :

     vin_bt |      Freq.     Percent        Cum.
------------+-----------------------------------
         2D |         11        0.79        0.79
         2H |         22        1.58        2.37
         2L |          1        0.07        2.44
         2P |          3        0.22        2.66
         2T |          1        0.07        2.73
         2W |          2        0.14        2.87
         3C |          4        0.29        3.16
         4C |         24        1.72        4.88
         4D |        383       27.49       32.38
         4H |         11        0.79       33.17
         4P |          1        0.07       33.24
         4W |         41        2.94       36.18
         5D |          3        0.22       36.40
         99 |         96        6.89       43.29
         BU |          6        0.43       43.72
         C4 |          1        0.07       43.79
         CB |         20        1.44       45.23
         CC |         33        2.37       47.60
         CG |         10        0.72       48.31
         CH |          1        0.07       48.38
         CP |         66        4.74       53.12
         CS |          1        0.07       53.19
         CV |         10        0.72       53.91
         CW |         33        2.37       56.28
         DP |          1        0.07       56.35
         DS |        112        8.04       64.39
         EC |          7        0.50       64.90
         ES |          2        0.14       65.04
         FC |          3        0.22       65.25
         GG |          1        0.07       65.33
         IC |         11        0.79       66.12
         IE |          3        0.22       66.33
         LB |          1        0.07       66.40
         LM |          1        0.07       66.48
         MH |          2        0.14       66.62
         MY |          1        0.07       66.69
         PC |         41        2.94       69.63
         PK |         90        6.46       76.09
         PS |         10        0.72       76.81
         RS |          7        0.50       77.32
         S2 |          1        0.07       77.39
         SV |         92        6.60       83.99
         SW |         21        1.51       85.50
         TB |          9        0.65       86.15
         TL |          5        0.36       86.50
         TM |         19        1.36       87.87
         UT |        160       11.49       99.35
         VN |          5        0.36       99.71
         VW |          1        0.07       99.78
         YY |          3        0.22      100.00
------------+-----------------------------------
      Total |      1,393      100.00

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