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

     Driver |
   Presence |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      9,825       98.25       98.25
          2 |         66        0.66       98.91
          3 |        109        1.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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