Frequencies for first 10,000 rows of spec variable in namcs2007 dataset :

  physician |
  specialty |      Freq.     Percent        Cum.
------------+-----------------------------------
        ADP |         10        0.10        0.10
         CD |         35        0.35        0.45
          D |         69        0.69        1.14
         EM |         35        0.35        1.49
        END |         31        0.31        1.80
         FP |      4,632       46.32       48.12
        FPS |         76        0.76       48.88
        FSM |         22        0.22       49.10
         GE |         20        0.20       49.30
         GP |        253        2.53       51.83
         GS |         30        0.30       52.13
         ID |         20        0.20       52.33
         IM |      1,878       18.78       71.11
        IMG |          2        0.02       71.13
        MPD |         25        0.25       71.38
          N |         81        0.81       72.19
         NS |         19        0.19       72.38
        OBG |         89        0.89       73.27
         OM |          6        0.06       73.33
        OPH |         71        0.71       74.04
        ORS |         93        0.93       74.97
         OS |         91        0.91       75.88
          P |         98        0.98       76.86
         PD |      2,073       20.73       97.59
         PG |         29        0.29       97.88
        PLM |         33        0.33       98.21
         PM |         38        0.38       98.59
        PMD |         14        0.14       98.73
        RHU |         46        0.46       99.19
         UM |         44        0.44       99.63
         VS |         37        0.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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