Frequencies for first 10,000 rows of ob_srvc_cd variable in pos2002 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,812       88.12       88.12
          0 |        594        5.94       94.06
          1 |        550        5.50       99.56
          2 |         32        0.32       99.88
          3 |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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