Frequencies for first 10,000 rows of psa variable in nhamcsopd2005 dataset :

   psa test |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,924       99.24       99.24
        yes |         76        0.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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