Frequencies for first 10,000 rows of tobaced variable in nhamcsopd2007 dataset : tobacco | use/exposur | e | Freq. Percent Cum. ------------+----------------------------------- no | 9,552 95.52 95.52 yes | 448 4.48 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016