This interactive bar chart displays FBI NICS firearm background check data aggregated by state and year, with stacked bars showing handgun, long gun, other, and multiple gun purchases. Users can filter by year, limit to top states, and sort bars by descending, ascending, or alphabetical order. Hovering reveals tooltip details, while legend interaction dims non-selected categories. The chart uses d3.scaleBand, d3.scaleLinear, d3.axisBottom, and d3.axisLeft, with d3-rosetta's unidirectional data flow managing state and re-rendering.