Frequencies for version variable in icd9sg2011 dataset :

   ICD-9-CM |
  Diagnosis |
        and |
  Procedure |
      Codes |      Freq.     Percent        Cum.
------------+-----------------------------------
         28 |      3,859      100.00      100.00
------------+-----------------------------------
      Total |      3,859      100.00

by Jean Roth , jroth@nber.org , 27 Apr 2017