Frequencies for first 10,000 rows of episode variable in nhamcsed2004 dataset :

episode of care |      Freq.     Percent        Cum.
----------------+-----------------------------------
          blank |        340        3.40        3.40
  initial visit |      8,753       87.53       90.93
follow-up visit |        643        6.43       97.36
        unknown |        264        2.64      100.00
----------------+-----------------------------------
          Total |     10,000      100.00

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