Frequencies for pvin_lngt variable in parkwork dataset :

 VIN length |      Freq.     Percent        Cum.
------------+-----------------------------------
         17 |      1,043       98.03       98.03
          . |         21        1.97      100.00
------------+-----------------------------------
      Total |      1,064      100.00

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