Frequencies for first 10,000 rows of rf_inftr variable in natlterr2012 dataset :

Infertility |
  Treatment |
        RFP |
590=f_rf_in |
   ft_drg R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      1,163       11.63       11.63
          N |      8,470       84.70       96.33
          U |        335        3.35       99.68
          Y |         32        0.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 5 May 2016