Frequencies for first 10,000 rows of prov1960 variable in pos1993 dataset :

       330e |
 toxicology |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,797       87.97       87.97
          N |        951        9.51       97.48
          Y |        252        2.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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