Frequencies for first 10,000 rows of psa variable in namcs2004 dataset :

   psa test |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,781       97.81       97.81
          1 |        219        2.19      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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