Frequencies for first 10,000 rows of spec variable in namcs2004 dataset :

  physician |
  specialty |      Freq.     Percent        Cum.
------------+-----------------------------------
         CD |        606        6.06        6.06
        CHP |        141        1.41        7.47
          D |        755        7.55       15.02
         FP |      1,305       13.05       28.07
         GE |         80        0.80       28.87
         GP |         69        0.69       29.56
         GS |        658        6.58       36.14
        GYN |         60        0.60       36.74
        HEM |         46        0.46       37.20
         HO |         21        0.21       37.41
         IM |        702        7.02       44.43
        IMG |         32        0.32       44.75
        MPD |         20        0.20       44.95
          N |        673        6.73       51.68
        NEP |         33        0.33       52.01
         NS |         36        0.36       52.37
        OBG |        542        5.42       57.79
         OM |         42        0.42       58.21
         ON |         90        0.90       59.11
        OPH |        459        4.59       63.70
        ORS |        574        5.74       69.44
         OS |         48        0.48       69.92
        OTO |        546        5.46       75.38
          P |        583        5.83       81.21
         PD |        870        8.70       89.91
         PS |         93        0.93       90.84
        PUD |         71        0.71       91.55
        RHU |         12        0.12       91.67
         TS |         61        0.61       92.28
          U |        675        6.75       99.03
         VS |         97        0.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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