Frequencies for first 10,000 rows of notobac variable in namcs2005 dataset :

      "if "not |
       current |
   checked for |
  tobacco use, |
      never or |
       former? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         Never |      4,960       49.60       49.60
        Former |        857        8.57       58.17
Not applicable |      3,495       34.95       93.12
         Blank |        688        6.88      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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