Frequencies for first 10,000 rows of staffphy variable in nhamcsopd1993 dataset :

      staff |
  physician |
       seen |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,883       28.83       28.83
          1 |      7,117       71.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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