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

Meningomyel |
    ocele / |
      Spina |
   Bifida 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 , 15 Jun 2016