Frequencies for first 10,000 rows of paydk variable in nhamcsed2011 dataset :

   Expected |
  source of |
   payment: |
    Unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,549       95.49       95.49
        Yes |        451        4.51      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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