Frequencies for first 10,000 rows of f_uca_anen variable in natlterr2005 dataset :

Anencephalu |
        s U |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,740       17.40       17.40
          1 |      8,260       82.60      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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