Frequencies for first 10,000 rows of ca_down variable in natl2013 dataset :

      Downs |
   Syndrome |
        RFP |
644=f_ca_do |
      wns R |      Freq.     Percent        Cum.
------------+-----------------------------------
          C |          1        0.01        0.01
          N |      9,991       99.91       99.92
          P |          8        0.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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