Frequencies for ser_tr variable in vehicle dataset :

 VIN SERIES |
      TRUCK |      Freq.     Percent        Cum.
------------+-----------------------------------
            |          1        0.21        0.21
        *** |        310       65.68       65.89
        30S |          1        0.21       66.10
        40S |          1        0.21       66.31
        600 |          1        0.21       66.53
        700 |          1        0.21       66.74
        70S |          2        0.42       67.16
        999 |         82       17.37       84.53
        ARO |          1        0.21       84.75
        AST |          1        0.21       84.96
        B22 |          4        0.85       85.81
        B23 |          1        0.21       86.02
        B30 |          2        0.42       86.44
        CAL |          1        0.21       86.65
        CHK |          2        0.42       87.08
        CMP |          1        0.21       87.29
        COF |          7        1.48       88.77
        COL |          1        0.21       88.98
        COM |          1        0.21       89.19
        CON |          5        1.06       90.25
        CTV |          2        0.42       90.68
        CVS |          1        0.21       90.89
        DRW |          1        0.21       91.10
        ECO |          1        0.21       91.31
        ELC |          1        0.21       91.53
        ENV |          1        0.21       91.74
        I35 |          1        0.21       91.95
        JEE |          1        0.21       92.16
        LIB |          2        0.42       92.58
        MMX |          1        0.21       92.80
        OFF |          1        0.21       93.01
        PRT |          1        0.21       93.22
        RAI |          1        0.21       93.43
        RMV |          1        0.21       93.64
        RNG |          8        1.69       95.34
        RPC |          1        0.21       95.55
          S |          3        0.64       96.19
        S/V |          1        0.21       96.40
        SAF |          1        0.21       96.61
        SIE |          1        0.21       96.82
        SRW |          1        0.21       97.03
         SS |          2        0.42       97.46
        STE |          1        0.21       97.67
        TAC |          4        0.85       98.52
        TRK |          1        0.21       98.73
        TUN |          1        0.21       98.94
        VAN |          1        0.21       99.15
        VOF |          1        0.21       99.36
        W/T |          1        0.21       99.58
        WIN |          1        0.21       99.79
        YUK |          1        0.21      100.00
------------+-----------------------------------
      Total |        472      100.00

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