Frequencies for ser_tr variable in vehicle dataset :

 VIN SERIES |
      TRUCK |      Freq.     Percent        Cum.
------------+-----------------------------------
            |         20        2.62        2.62
        *** |        534       69.90       72.51
        40S |          1        0.13       72.64
        600 |          4        0.52       73.17
        700 |          2        0.26       73.43
        720 |          1        0.13       73.56
        999 |         98       12.83       86.39
        ACL |          1        0.13       86.52
        ARO |          3        0.39       86.91
        AST |          4        0.52       87.43
        B20 |          1        0.13       87.57
        B22 |          1        0.13       87.70
        B23 |          4        0.52       88.22
        B30 |          2        0.26       88.48
        BRO |          2        0.26       88.74
        BUS |          1        0.13       88.87
        C10 |          2        0.26       89.14
        C15 |          2        0.26       89.40
        CHK |          3        0.39       89.79
        CLU |          1        0.13       89.92
        COF |         21        2.75       92.67
        COL |          2        0.26       92.93
        COM |          1        0.13       93.06
        COU |          2        0.26       93.32
        CTV |          1        0.13       93.46
        CVS |          5        0.65       94.11
        CWS |          1        0.13       94.24
        D30 |          1        0.13       94.37
        GCK |          1        0.13       94.50
        GM4 |          1        0.13       94.63
        HTP |          5        0.65       95.29
        JEE |          6        0.79       96.07
        K10 |          1        0.13       96.20
        KOD |          1        0.13       96.34
        MAX |          2        0.26       96.60
        MHV |          3        0.39       96.99
        MMX |          2        0.26       97.25
        P20 |          1        0.13       97.38
        RNG |          3        0.39       97.77
        SAF |          3        0.39       98.17
        TNS |          1        0.13       98.30
        UNI |          2        0.26       98.56
        VAN |          8        1.05       99.61
        VWG |          1        0.13       99.74
        XCN |          1        0.13       99.87
        YUK |          1        0.13      100.00
------------+-----------------------------------
      Total |        764      100.00

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