Frequencies for first 10,000 rows of episode variable in nhamcsopd2001 dataset :

episode of care |      Freq.     Percent        Cum.
----------------+-----------------------------------
          Blank |        716        7.16        7.16
  Initial visit |      2,085       20.85       28.01
Follow-up visit |      4,671       46.71       74.72
        Unknown |        255        2.55       77.27
 Not applicable |      2,273       22.73      100.00
----------------+-----------------------------------
          Total |     10,000      100.00

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