Frequencies for first 10,000 rows of uca_ompha variable in natl2013 dataset :

Omphalocele |
/Gastroschi |
    sis RFP |
761=f_uca_o |
 mphalo U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         11        0.11        0.11
          2 |      9,989       99.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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