Frequencies for first 10,000 rows of ob_srvc_cd variable in pos2003 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,789       87.89       87.89
          0 |        614        6.14       94.03
          1 |        550        5.50       99.53
          2 |         33        0.33       99.86
          3 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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