Frequencies for d_vision3 variable in vehicle dataset :

 DRI VISION |
OBSCURED BY |
          3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        472      100.00      100.00
------------+-----------------------------------
      Total |        472      100.00

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