Frequencies for first 10,000 rows of hpvdna variable in nhamcsopd2007 dataset :

        hpv |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,930       99.30       99.30
        yes |         70        0.70      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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