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

  chlamydia |
       test |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,796       97.96       97.96
        yes |        204        2.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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