Frequencies for first 10,000 rows of phys variable in namcs1998 dataset :

  physician |
       seen |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        364        3.64        3.64
          1 |      9,636       96.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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