Frequencies for first 10,000 rows of prov1980 variable in pos1993 dataset :

   520   rh |
     titers |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,797       87.97       87.97
          N |      1,013       10.13       98.10
          Y |        190        1.90      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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