Frequencies for first 10,000 rows of rf_ghyp variable in linkpe2009psden dataset :

Gestational |
Hypertensio |
        n R |
(f_rf_ghype |
r rep flag) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      3,422       34.22       34.22
          N |      6,356       63.56       97.78
          U |          1        0.01       97.79
          Y |        221        2.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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