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

  Services: |
 Obstetrics |
       Code |      Freq.     Percent        Cum.
------------+-----------------------------------
          . |      8,601       86.01       86.01
          0 |        775        7.75       93.76
          1 |        547        5.47       99.23
          2 |         40        0.40       99.63
          3 |         37        0.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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