Frequencies for first 10,000 rows of ob_srvc_cd variable in pos2007 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,682       86.82       86.82
          0 |        693        6.93       93.75
          1 |        575        5.75       99.50
          2 |         33        0.33       99.83
          3 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017