Frequencies for first 10,000 rows of paydk variable in nhamcsed2012 dataset :

   Expected |
  source of |
   payment: |
    Unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,375       93.75       93.75
        Yes |        625        6.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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