Frequencies for first 10,000 rows of noopteff variable in nhamcsed2007 dataset :

  does your |
ed use none |
     of the |
     above? |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,525       95.25       95.25
        yes |        475        4.75      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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