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

Anencephalu |
          s |
 (uca_anen) |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,178       21.78       21.78
          1 |      7,822       78.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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