Frequencies for first 10,000 rows of f_uca_downs variable in natl2011 dataset :

       Down |
   Syndrome |
(ucs_downs) |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |     10,000      100.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015