Frequencies for first 10,000 rows of proc variable in nhamcsed2004 dataset :

   were any |
 procedures |
provided at |
this visit? |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      4,472       44.72       44.72
        yes |      4,956       49.56       94.28
  no answer |        572        5.72      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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