Frequencies for first 10,000 rows of d_vision3 variable in vehicle dataset :

 DRI VISION |
OBSCURED BY |
          3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,660       96.60       96.60
         99 |        340        3.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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