Frequencies for first 10,000 rows of rf_gest variable in natlterr2009 dataset :

Gestational |
   Diabetes |
        RFP |
583=f_rf_gd |
      iab R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      2,449       24.49       24.49
          N |      7,386       73.86       98.35
          U |          2        0.02       98.37
          Y |        163        1.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015