Frequencies for first 10,000 rows of paydk variable in nhamcsed2010 dataset :

   Expected |
  source of |
   payment: |
    Unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,521       95.21       95.21
        yes |        479        4.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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