Frequencies for first 10,000 rows of usetobac variable in nhamcsopd2001 dataset :

       does |
patient use |
   tobacco? |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        565        5.65        5.65
          1 |        766        7.66       13.31
          2 |      3,774       37.74       51.05
          3 |      4,895       48.95      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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