Frequencies for first 10,000 rows of evertobac variable in namcs2015 dataset :

      Prior |
tobacco use |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      2,617       26.17       26.17
         -8 |        860        8.60       34.77
          1 |      5,030       50.30       85.07
          2 |      1,493       14.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 25 Oct 2017