Frequencies for first 10,000 rows of bac variable in nhamcsed2002 dataset : blood | alcohol | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,799 97.99 97.99 1 | 201 2.01 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016