Frequencies for first 10,000 rows of prev_dwi variable in vehicle dataset :

   PREVIOUS |
        DWI |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,959       89.59       89.59
          1 |        385        3.85       93.44
          2 |         70        0.70       94.14
          3 |         27        0.27       94.41
          4 |          4        0.04       94.45
          5 |          1        0.01       94.46
          7 |          1        0.01       94.47
          9 |          1        0.01       94.48
         99 |        552        5.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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