Frequencies for first 10,000 rows of combination variable in icd9toicd10cmgem dataset :

Combination |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,864       98.64       98.64
          1 |        136        1.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 11 May 2016