Frequencies for end_datestr variable in hqi_op_procedure_volume dataset :

   End Date |      Freq.     Percent        Cum.
------------+-----------------------------------
 12/31/2013 |      4,103      100.00      100.00
------------+-----------------------------------
      Total |      4,103      100.00

by Jean Roth , jroth@nber.org , 16 Nov 2016