Frequencies for first 10,000 rows of selfpay variable in nhamcsopd1992 dataset :

   Expected |
  source of |
payment-Pat |
  ient paid |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,671       86.71       86.71
          1 |      1,329       13.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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