Frequencies for first 10,000 rows of episode variable in nhamcsed2012 dataset :

Episode of care |      Freq.     Percent        Cum.
----------------+-----------------------------------
          Blank |        506        5.06        5.06
        Unknown |        524        5.24       10.30
  Initial visit |      8,426       84.26       94.56
Follow-up visit |        544        5.44      100.00
----------------+-----------------------------------
          Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016