Frequencies for first 10,000 rows of pregnant variable in namcs1998 dataset :

 if female, |
 is patient |
  pregnant? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        226        2.26        2.26
          2 |      5,033       50.33       52.59
          3 |        501        5.01       57.60
          4 |      4,240       42.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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