Frequencies for pvin_4 variable in parkwork dataset :

        vin |
character(4 |
          ) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          6        0.55        0.55
          1 |         10        0.92        1.47
          2 |          4        0.37        1.84
          3 |          3        0.28        2.11
          4 |          6        0.55        2.66
          5 |          6        0.55        3.21
          6 |          6        0.55        3.76
          7 |          4        0.37        4.13
          8 |          1        0.09        4.22
          9 |         28        2.57        6.80
          A |         87        7.99       14.78
          B |         89        8.17       22.96
          C |         60        5.51       28.47
          D |         84        7.71       36.18
          E |         81        7.44       43.62
          F |         73        6.70       50.32
          G |         52        4.78       55.10
          H |         80        7.35       62.44
          J |         56        5.14       67.58
          K |         33        3.03       70.62
          L |         20        1.84       72.45
          M |         31        2.85       75.30
          N |         39        3.58       78.88
          P |         19        1.74       80.62
          R |         39        3.58       84.21
          S |         27        2.48       86.69
          T |          6        0.55       87.24
          U |         21        1.93       89.16
          V |          5        0.46       89.62
          W |         45        4.13       93.76
          X |         13        1.19       94.95
          Y |         23        2.11       97.06
          Z |         32        2.94      100.00
------------+-----------------------------------
      Total |      1,089      100.00

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