Frequencies for first 10,000 rows of mammo variable in namcs2015 dataset :

Mammography |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,833       98.33       98.33
          1 |        167        1.67      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 25 Oct 2017