Frequencies for first 10,000 rows of dr_sf4 variable in vehicle dataset :

     driver |
    related |
 factors (4 |
   choices) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,565       95.65       95.65
          6 |          1        0.01       95.66
         91 |          6        0.06       95.72
         99 |        428        4.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016