Frequencies for first 10,000 rows of catscan variable in nhamcsed2010 dataset :

   CAT scan |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      8,312       83.12       83.12
        yes |      1,688       16.88      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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