Frequencies for first 10,000 rows of sched1 variable in nhamcsopd1992 dataset :

        Was |
   surgical |
  procedure |
         #1 |
  scheduled |
         or |
 performed? |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,459       94.59       94.59
          1 |        212        2.12       96.71
          2 |        329        3.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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