Frequencies for first 10,000 rows of prov1970 variable in pos1994 dataset :

        500 |
immunohemat |
      ology |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,798       87.98       87.98
          N |      1,155       11.55       99.53
          Y |         47        0.47      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017