Frequencies for first 10,000 rows of electrol variable in namcs2005 dataset : electrolyte | s | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,345 93.45 93.45 1 | 655 6.55 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016