Surveys of the smoke composition of commercially marketed cigarettes were conducted in 1995, 1998, and 2000. For each of these surveys, the U.S. cigarette market was stratified into broad market sections based on "tar" category and menthol inclusion. Brand styles were selected from these market sections using techniques in which selection probability increased with increasing market share. Nineteen mainstream smoke constituents were evaluated. In addition, carbon dioxide values were obtained on all brand styles selected in 1998 and 2000. Collectively, the results of these surveys provide evidence that constituent yields are, in general, proportional to "tar" yield and that the relationships between constituent yields and "tar" have remained constant during this time span. Moreover, these data demonstrate that constituent yields of commercially marketed cigarettes available in the U.S. between 1995 and 2000 have been effectively constant.