Frequencies for vin_bt variable in person dataset :

     vin_bt |      Freq.     Percent        Cum.
------------+-----------------------------------
            |        198       18.38       18.38
         2D |         47        4.36       22.75
         2H |         80        7.43       30.18
         2L |          3        0.28       30.45
         2W |          4        0.37       30.83
         3C |          3        0.28       31.10
         3P |          2        0.19       31.29
         4C |          3        0.28       31.57
         4D |        225       20.89       52.46
         4H |         10        0.93       53.39
         4P |          2        0.19       53.57
         4W |         11        1.02       54.60
         99 |        114       10.58       65.18
         BU |          1        0.09       65.27
         CB |          3        0.28       65.55
         CC |          6        0.56       66.11
         CG |          7        0.65       66.76
         CP |         48        4.46       71.22
         CV |          1        0.09       71.31
         CW |          9        0.84       72.14
         DP |          3        0.28       72.42
         DS |          3        0.28       72.70
         ES |          1        0.09       72.79
         FC |          1        0.09       72.89
         GL |          2        0.19       73.07
         IE |          2        0.19       73.26
         PC |         21        1.95       75.21
         PK |         43        3.99       79.20
         PS |          2        0.19       79.39
         RS |         59        5.48       84.87
         S2 |          1        0.09       84.96
         SV |         17        1.58       86.54
         SW |         42        3.90       90.44
         TB |          1        0.09       90.53
         TL |          1        0.09       90.62
         TM |          8        0.74       91.36
         UT |         90        8.36       99.72
         VN |          2        0.19       99.91
         YY |          1        0.09      100.00
------------+-----------------------------------
      Total |      1,077      100.00

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