Frequencies for first 10,000 rows of ca_down variable in natlterr2013 dataset :

      Downs |
   Syndrome |
        RFP |
644=f_ca_do |
      wns R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      1,077       10.77       10.77
          C |          3        0.03       10.80
          N |      8,551       85.51       96.31
          P |          6        0.06       96.37
          U |        363        3.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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