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

    Is patient |
     pregnant? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         Blank |      3,498       34.98       34.98
Not applicable |      4,220       42.20       77.18
           Yes |        403        4.03       81.21
            No |      1,879       18.79      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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