Frequencies for first 10,000 rows of pregtest variable in namcs2013 dataset :

  Pregnancy |
   test/HCG |
       test |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,937       99.37       99.37
        Yes |         63        0.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Mar 2017