Frequencies for first 10,000 rows of othultra variable in nhamcsopd2011 dataset : Other | ultrasound | Freq. Percent Cum. ------------+----------------------------------- No | 9,517 95.17 95.17 Yes | 483 4.83 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016