Frequencies for first 10,000 rows of pregnant variable in namcs2005 dataset :

 if female, is |
       patient |
     pregnant? |      Freq.     Percent        Cum.
---------------+-----------------------------------
           Yes |         67        0.67        0.67
            No |      4,745       47.45       48.12
       Unknown |        317        3.17       51.29
Not applicable |      4,595       45.95       97.24
         Blank |        276        2.76      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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