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

Gestational |
Hypertensio |
      n RFP |
585=f_rf_gh |
     yper R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      1,163       11.63       11.63
          N |      8,316       83.16       94.79
          U |        335        3.35       98.14
          Y |        186        1.86      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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