Frequencies for first 10,000 rows of prov4175 variable in posclia2006 dataset :

   multiple |
       site |
certificate |
        ind |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      3,123       31.23       31.23
          N |      6,429       64.29       95.52
          Y |        448        4.48      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016