Frequencies for first 10,000 rows of rh variable in natl1989 dataset :

         Rh |
sensitizati |
         on |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         59        0.59        0.59
          2 |      9,738       97.38       97.97
          9 |        203        2.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016