Frequencies for first 10,000 rows of physn_srvc_cd variable in pos2015 dataset 

  Services: |
  Physician |
       Code |      Freq.     Percent        Cum.
------------+-----------------------------------
          . |      9,290       92.90       92.90
          1 |        473        4.73       97.63
          2 |        223        2.23       99.86
          3 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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