Frequencies for first 10,000 rows of op_tocol variable in natlterr2008 dataset :

  Tocolysis |
        RFP |
602=f_ob_to |
       co R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,061       60.61       60.61
          N |      3,856       38.56       99.17
          Y |         83        0.83      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016