Frequencies for first 10,000 rows of ca_down variable in natlterr2011 dataset :

      Downs |
   Syndrome |
        RFP |
644=f_ca_do |
      wns R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      2,536       25.36       25.36
          C |          2        0.02       25.38
          N |      6,361       63.61       88.99
          P |          5        0.05       89.04
          U |      1,096       10.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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