Frequencies for first 10,000 rows of proc variable in nhamcsed2002 dataset :

   were any |
 procedures |
provided at |
this visit? |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      5,124       51.24       51.24
        Yes |      4,160       41.60       92.84
  No answer |        716        7.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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