Frequencies for first 10,000 rows of ob_srvc_cd variable in pos2006 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,710       87.10       87.10
          0 |        669        6.69       93.79
          1 |        571        5.71       99.50
          2 |         35        0.35       99.85
          3 |         15        0.15      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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