Frequencies for pvin_7 variable in parkwork dataset :

        vin |
character(7 |
          ) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |          2        0.18        0.18
          0 |         41        3.76        3.94
          1 |         98        8.98       12.92
          2 |        134       12.28       25.21
          3 |         99        9.07       34.28
          4 |         88        8.07       42.35
          5 |         73        6.69       49.04
          6 |         93        8.52       57.56
          7 |         44        4.03       61.59
          8 |         89        8.16       69.75
          9 |        117       10.72       80.48
          A |         37        3.39       83.87
          B |         12        1.10       84.97
          C |         32        2.93       87.90
          D |         35        3.21       91.11
          E |         30        2.75       93.86
          F |         19        1.74       95.60
          G |          6        0.55       96.15
          H |          4        0.37       96.52
          J |          7        0.64       97.16
          K |          1        0.09       97.25
          L |          1        0.09       97.34
          M |          2        0.18       97.53
          N |          1        0.09       97.62
          P |          8        0.73       98.35
          R |          2        0.18       98.53
          S |          5        0.46       98.99
          T |          8        0.73       99.73
          U |          1        0.09       99.82
          W |          1        0.09       99.91
          Z |          1        0.09      100.00
------------+-----------------------------------
      Total |      1,091      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016