Frequencies for first 10,000 rows of usetobac variable in nhamcsopd2002 dataset :

       does |
patient use |
   tobacco? |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        390        3.90        3.90
          1 |        750        7.50       11.40
          2 |      4,162       41.62       53.02
          3 |      4,698       46.98      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016