Frequencies for first 10,000 rows of uca_anen variable in natl2012 dataset :

Anencephalu |
      s RFP |
752=f_uca_a |
    nen U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |      7,557       75.57       75.57
          9 |      2,443       24.43      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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