Frequencies for first 10,000 rows of prov1975 variable in pos1993 dataset :

510   abo + |
   rh group |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,797       87.97       87.97
          N |        883        8.83       96.80
          Y |        320        3.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016