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

Anencephaly |
          R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,255       62.55       62.55
          N |      3,745       37.45      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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