Frequencies for first 10,000 rows of payself variable in nhamcsed2012 dataset :

   Expected |
  source of |
   payment: |
   Self pay |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      8,704       87.04       87.04
        Yes |      1,296       12.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016