Frequencies for first 10,000 rows of ca_cdh variable in natl2015 dataset :

 Congenital |
Diaphragmat |
ic Hernia Y |
        Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,998       99.98       99.98
          U |          1        0.01       99.99
          Y |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Oct 2016