Frequencies for first 10,000 rows of othultra variable in namcs2009 dataset :

      other |
 ultrasound |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,798       97.98       97.98
        yes |        202        2.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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