Frequencies for first 10,000 rows of othultra variable in namcs2012 dataset :

      Other |
 ultrasound |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,713       97.13       97.13
        Yes |        287        2.87      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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