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

Prepregnanc |
          y |
Hypertensio |
      n RFP |
584=f_rf_ph |
     yper R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,061       60.61       60.61
          N |      3,901       39.01       99.62
          Y |         38        0.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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