Frequencies for first 10,000 rows of amb variable in nhamcsopd1997 dataset :

       were |
 ambulatory |
   surgical |
      procs |
 performed? |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,575       95.75       95.75
        Yes |        425        4.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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