Frequencies for first 10,000 rows of ca_gast variable in natl2011 dataset :

Gastroschis |
     is RFP |
640=f_ca_ga |
     stro R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |     10,000      100.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015