Frequencies for first 10,000 rows of physn_srvc_cd variable in pos2013 dataset 

  Services: |
  Physician |
       Code |      Freq.     Percent        Cum.
------------+-----------------------------------
          . |      9,324       93.24       93.24
          1 |        466        4.66       97.90
          2 |        192        1.92       99.82
          3 |         18        0.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016