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

   PREVIOUS |
        DWI |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,814       88.14       88.14
          1 |        448        4.48       92.62
          2 |        119        1.19       93.81
          3 |         22        0.22       94.03
          4 |          6        0.06       94.09
          5 |          1        0.01       94.10
         99 |        590        5.90      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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