Frequencies for first 10,000 rows of paydk variable in nhamcsopd2007 dataset :

   expected |
  source of |
   payment: |
    unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,156       91.56       91.56
        yes |        844        8.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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