Frequencies for first 10,000 rows of ca_omph variable in natl2017 dataset :

Omphalocele |
      Y Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,997       99.97       99.97
          Y |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Sep 2018