Multivariate regression results: Relationship between population density of passenger vehicles manufactured before 1986 and 1999, respectively, and rates of suicide by motor vehicle exhaust.

Not shown are continuous variables included in the regression models that indicated the percentages of the population in each postcode-year for whom, respectively, educational status, employment status, region of birth, Aboriginal or Torres Strait Islander race, and income level were not known. None of those variables was statistically significant. Both models also controlled for year using dummy variables.aThe reference categories are: 25–64 y (age); year 11 or 12 (final year of education); employed; married; non-Christian; born outside Oceania; not Aboriginal or Torres Strait Islander; and middle income.