Frequencies for first 10,000 rows of tobacco variable in natl1991 dataset :

Tobacco Use |
     During |
  Pregnancy |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,647       16.47       16.47
          2 |      8,342       83.42       99.89
          9 |         11        0.11      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015