Frequencies for first 10,000 rows of exam variable in namcs2010 dataset :

  exam code |
       from |
   icd-9-cm |
 procedures |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      7,936       79.36       79.36
        yes |      2,064       20.64      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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