Frequencies for first 10,000 rows of paydk variable in nhamcsopd2011 dataset :

   Expected |
  source of |
  payment - |
    Unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,419       94.19       94.19
        Yes |        581        5.81      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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