Frequencies for first 10,000 rows of rh variable in natl1994 dataset :

         Rh |
sensitizati |
         on |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         25        0.25        0.25
          2 |      9,927       99.27       99.52
          8 |          1        0.01       99.53
          9 |         47        0.47      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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