Frequencies for first 10,000 rows of vyear variable in nhamcsed1994 dataset : year of | visit - 2 | digits | Freq. Percent Cum. ------------+----------------------------------- 93 | 108 1.08 1.08 94 | 9,892 98.92 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016