Frequencies for first 10,000 rows of ob_srvc_cd variable in pos2004 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,766       87.66       87.66
          0 |        634        6.34       94.00
          1 |        548        5.48       99.48
          2 |         38        0.38       99.86
          3 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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