Frequencies for first 10,000 rows of ob_srvc_cd variable in pos1991 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,770       87.70       87.70
          0 |        572        5.72       93.42
          1 |        612        6.12       99.54
          2 |         41        0.41       99.95
          3 |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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