Frequencies for first 10,000 rows of psa variable in namcs2005 dataset : psa test | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,807 98.07 98.07 1 | 193 1.93 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016