Frequencies for first 10,000 rows of amb variable in namcs2000 dataset :

       were |
 ambulatory |
   surgical |
      procs |
  performed |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,332       93.32       93.32
        Yes |        310        3.10       96.42
 Item blank |        358        3.58      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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