Frequencies for first 10,000 rows of mammo variable in namcs2003 dataset :

  mammogram |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,840       98.40       98.40
          1 |        160        1.60      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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