Frequencies for pvin_12 variable in parkwork dataset :

        VIN |
Character(1 |
         2) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |         12        1.13        1.13
          0 |        151       14.19       15.32
          1 |        220       20.68       36.00
          2 |        133       12.50       48.50
          3 |         60        5.64       54.14
          4 |         48        4.51       58.65
          5 |         86        8.08       66.73
          6 |         61        5.73       72.46
          7 |         29        2.73       75.19
          8 |         21        1.97       77.16
          9 |         42        3.95       81.11
          A |         73        6.86       87.97
          B |         49        4.61       92.58
          C |         14        1.32       93.89
          D |         12        1.13       95.02
          E |          4        0.38       95.39
          F |          5        0.47       95.86
          G |          1        0.09       95.96
          H |          4        0.38       96.33
          J |          5        0.47       96.80
          K |          5        0.47       97.27
          L |          3        0.28       97.56
          M |          7        0.66       98.21
          N |          3        0.28       98.50
          R |          1        0.09       98.59
          S |          2        0.19       98.78
          T |          1        0.09       98.87
          U |          2        0.19       99.06
          V |          3        0.28       99.34
          W |          2        0.19       99.53
          X |          2        0.19       99.72
          Y |          2        0.19       99.91
          Z |          1        0.09      100.00
------------+-----------------------------------
      Total |      1,064      100.00

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