Frequencies for pvin_4 variable in parkwork dataset :

        VIN |
Character(4 |
          ) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |          2        0.19        0.19
          0 |         10        0.94        1.13
          1 |          7        0.66        1.79
          2 |          6        0.56        2.35
          3 |          2        0.19        2.54
          5 |          9        0.85        3.38
          6 |          1        0.09        3.48
          7 |          2        0.19        3.67
          9 |         33        3.10        6.77
          A |         64        6.02       12.78
          B |         67        6.30       19.08
          C |         87        8.18       27.26
          D |         75        7.05       34.30
          E |        102        9.59       43.89
          F |         63        5.92       49.81
          G |         76        7.14       56.95
          H |         64        6.02       62.97
          J |         63        5.92       68.89
          K |         33        3.10       71.99
          L |         25        2.35       74.34
          M |         15        1.41       75.75
          N |         43        4.04       79.79
          P |         19        1.79       81.58
          R |         40        3.76       85.34
          S |         26        2.44       87.78
          T |          5        0.47       88.25
          U |         10        0.94       89.19
          V |         10        0.94       90.13
          W |         40        3.76       93.89
          X |         13        1.22       95.11
          Y |         17        1.60       96.71
          Z |         35        3.29      100.00
------------+-----------------------------------
      Total |      1,064      100.00

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