Frequencies for first 10,000 rows of urf_rh variable in natl2003 dataset :

         Rh |
sensitizati |
       on U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         30        0.30        0.30
          2 |      9,147       91.47       91.77
          8 |          8        0.08       91.85
          9 |        815        8.15      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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