Frequencies for first 10,000 rows of popsum variable in namcs1994 dataset : # of clinic | sampling | units in | hos (=0 for | namcs) | Freq. Percent Cum. ------------+----------------------------------- 0 | 10,000 100.00 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016