Frequencies for first 10,000 rows of episode variable in nhamcsed2007 dataset :

episode of care |      Freq.     Percent        Cum.
----------------+-----------------------------------
          blank |        427        4.27        4.27
        unknown |        938        9.38       13.65
  initial visit |      7,841       78.41       92.06
follow-up visit |        794        7.94      100.00
----------------+-----------------------------------
          Total |     10,000      100.00

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