Frequencies for first 10,000 rows of skin variable in namcs2007 dataset :

  skin exam |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      8,628       86.28       86.28
        yes |      1,372       13.72      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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