Frequencies for first 10,000 rows of telephon variable in nhamcsopd1999 dataset : telephone | follow-up | planned | Freq. Percent Cum. ------------+----------------------------------- 0 | 9,553 95.53 95.53 1 | 447 4.47 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016