Frequencies for first 10,000 rows of mammo variable in namcs2002 dataset :

  Mammogram |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,843       98.43       98.43
        Yes |        157        1.57      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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