Frequencies for first 10,000 rows of retappt variable in nhamcsopd1995 dataset : return at | specified | time | Freq. Percent Cum. ------------+----------------------------------- 0 | 2,733 27.33 27.33 1 | 7,267 72.67 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016