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

     DRIVER |
   PRESENCE |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      9,818       98.18       98.18
          2 |         88        0.88       99.06
          3 |         94        0.94      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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