Frequencies for first 10,000 rows of tobaced variable in nhamcsopd2008 dataset : tobacco | use/exposur | e | Freq. Percent Cum. ------------+----------------------------------- no | 9,716 97.16 97.16 yes | 284 2.84 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016