Frequencies for first 10,000 rows of spec variable in namcs1995 dataset :

  physician |
  specialty |      Freq.     Percent        Cum.
------------+-----------------------------------
        ADL |         46        0.46        0.46
        ADM |          2        0.02        0.48
         CD |         17        0.17        0.65
        CRS |         36        0.36        1.01
          D |         81        0.81        1.82
         EM |         93        0.93        2.75
         FP |      2,723       27.23       29.98
         GE |         45        0.45       30.43
         GP |      3,276       32.76       63.19
         GS |         78        0.78       63.97
         IM |      3,119       31.19       95.16
          N |         11        0.11       95.27
         NS |         16        0.16       95.43
        OBG |         95        0.95       96.38
         ON |         14        0.14       96.52
        OPH |         68        0.68       97.20
        ORS |        101        1.01       98.21
         OS |         61        0.61       98.82
        OTO |          9        0.09       98.91
          P |         16        0.16       99.07
         PD |         24        0.24       99.31
         PH |         32        0.32       99.63
         TS |          8        0.08       99.71
          U |         29        0.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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