Frequencies for first 10,000 rows of mri variable in nhamcsed2009 dataset : mri | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,932 99.32 99.32 1 | 68 0.68 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016