Current smoking was defined as smoking all or part of a cigarette within the 30 days preceding the interview. Among current smokers, daily smoking was defined as smoking every day in the past 30 days. Ever smoking was defined as adults who smoked at least 100 cigarettes in their lifetimes. The quit ratio was calculated as the percentage of adults who had ever smoked ≥100 cigarettes and who also reported no past month cigarette use. Current smoking was examined by age, race/ethnicity, education, poverty status, U.S. Census region, and year (https://www.census.gov/hhes/www/poverty/data/threshld/index.html), both overall and by sex. Persons identified as Hispanic might be of any race. Persons identified as white, black, Asian, American Indian/Alaska Native, or Other were all non-Hispanic. The six racial/ethnic categories were mutually exclusive. Other included Native Hawaiians or Other Pacific Islanders and persons of two or more races. Poverty status was defined using poverty thresholds published by the U.S. Census Bureau. Data were weighted during analysis to adjust for the differential probability of both selection and response. Statistical significance of observed differences was assessed using chi-square tests
