Frequencies for first 10,000 rows of refphys variable in namcs1999 dataset :

returned to |
  referring |
  physician |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,805       98.05       98.05
          1 |        195        1.95      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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