You acknowledged the statistic is a correlation earlier. There are also many other correlations with lower gun homicides in the US. The causation is the interes

You acknowledged the statistic is a correlation earlier. There are also many other correlations with lower gun homicides in the US. The causation is the interesting fact, and harder to determine. The argument that increasing gun sales causes lower gun homicides fails some logic and common sense tests, and would need evidence before anyone takes it seriously. Until then, it is seems more likely that other factors that we do have evidence for (eg. lower lead exposure leading to a drop in violent crime across the board) is causing the lowering of gun homicide in the US, despite the fact that gun sales are increasing.