Frequencies for first 10,000 rows of cig_1 variable in natl2008 dataset :

 Cigarettes |
        1st |
  Trimester |
        RFP |
575=f_tobac |
        o R |      Freq.     Percent        Cum.
------------+-----------------------------------
          . |     10,000      100.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016