Frequencies for first 10,000 rows of prov1920 variable in pos1994 dataset :

        200 |
 diagnostic |
 immunology |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,798       87.98       87.98
          N |        770        7.70       95.68
          Y |        432        4.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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