Frequencies for first 10,000 rows of pregnant variable in namcs1999 dataset :

 if female, |
 is patient |
  pregnant? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        216        2.16        2.16
          2 |      4,650       46.50       48.66
          3 |        784        7.84       56.50
          4 |      4,350       43.50      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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