Frequencies for first 10,000 rows of pregtest variable in nhamcsed2010 dataset :

  Pregnancy |
       test |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,369       93.69       93.69
        yes |        631        6.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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