Frequencies for first 10,000 rows of paydk variable in nhamcsed2013 dataset :

   Expected |
  source of |
   payment: |
    Unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      8,964       89.64       89.64
        Yes |      1,036       10.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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