Frequencies for first 10,000 rows of episode variable in nhamcsed2015 dataset :

           Episode of care |      Freq.     Percent        Cum.
---------------------------+-----------------------------------
                     Blank |         95        0.95        0.95
                   Unknown |        273        2.73        3.68
  Initial visit to this ED |      9,118       91.18       94.86
Follow-up visit to this ED |        514        5.14      100.00
---------------------------+-----------------------------------
                     Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Nov 2017