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

   PREVIOUS |
        DWI |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,178       91.78       91.78
          1 |        299        2.99       94.77
          2 |         55        0.55       95.32
          3 |          9        0.09       95.41
          4 |          5        0.05       95.46
          5 |          2        0.02       95.48
         99 |        373        3.73       99.21
          . |         79        0.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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