Frequencies for first 10,000 rows of spec variable in namcs1996 dataset :

  physician |
  specialty |      Freq.     Percent        Cum.
------------+-----------------------------------
          A |         22        0.22        0.22
        ADL |         13        0.13        0.35
         AI |         68        0.68        1.03
         CD |        560        5.60        6.63
        CDS |         16        0.16        6.79
        CHN |          2        0.02        6.81
        CHP |         45        0.45        7.26
        CRS |          6        0.06        7.32
          D |        737        7.37       14.69
         EM |          2        0.02       14.71
        END |         60        0.60       15.31
         FP |      1,888       18.88       34.19
        FPG |          8        0.08       34.27
        FSM |          6        0.06       34.33
         GE |        191        1.91       36.24
         GP |        439        4.39       40.63
        GPM |         10        0.10       40.73
         GS |        470        4.70       45.43
        GYN |         50        0.50       45.93
        HEM |          1        0.01       45.94
        HNS |          9        0.09       46.03
        HSO |         36        0.36       46.39
         ID |         17        0.17       46.56
         IM |      1,468       14.68       61.24
          N |        349        3.49       64.73
        NEP |         82        0.82       65.55
         NS |         30        0.30       65.85
        NSP |          1        0.01       65.86
        OBG |        376        3.76       69.62
        OBS |         11        0.11       69.73
         OM |         16        0.16       69.89
         ON |         87        0.87       70.76
         OP |          2        0.02       70.78
        OPH |        365        3.65       74.43
        ORS |        412        4.12       78.55
         OS |         12        0.12       78.67
        OSM |          2        0.02       78.69
        OSS |          1        0.01       78.70
        OTO |        392        3.92       82.62
          P |        385        3.85       86.47
         PD |        834        8.34       94.81
        PDE |          1        0.01       94.82
         PH |          8        0.08       94.90
        PHO |         17        0.17       95.07
         PM |         82        0.82       95.89
         PS |         27        0.27       96.16
        PUD |         62        0.62       96.78
        RHU |         17        0.17       96.95
         TS |          1        0.01       96.96
          U |        220        2.20       99.16
         UP |          3        0.03       99.19
         US |         68        0.68       99.87
         VS |         13        0.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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