Frequencies for first 10,000 rows of retappt variable in nhamcsopd2001 dataset : return, | appt. | Freq. Percent Cum. ------------+----------------------------------- 0 | 2,529 25.29 25.29 1 | 7,471 74.71 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016