Frequencies for first 10,000 rows of ca_anen variable in natl2014 dataset :

Anencephaly |
      Y Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,999       99.99       99.99
          Y |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016