Frequencies for first 10,000 rows of ob_srvc_cd variable in pos1994 dataset :

       srv: |
 obstetrics |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,940       89.40       89.40
          0 |        493        4.93       94.33
          1 |        538        5.38       99.71
          2 |         26        0.26       99.97
          3 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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