Frequencies for first 10,000 rows of refphys variable in namcs1994 dataset :

returned to |
  referring |
  physician |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,879       98.79       98.79
          1 |        121        1.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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