Frequencies for first 10,000 rows of payself variable in nhamcsed2007 dataset :

   self pay |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      8,138       81.38       81.38
        yes |      1,862       18.62      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016