Frequencies for first 10,000 rows of prov1880 variable in pos1993 dataset :

        100 |
microbiolog |
          y |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,797       87.97       87.97
          N |      1,183       11.83       99.80
          Y |         20        0.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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