This visualization uses an interactive bar chart to show the total number of firearms by state for a selected year, with bars stacked and colored by firearm type (handgun, long gun, other, multiple). Users can filter to the top 10 or 25 states or view all. The D3.js example loads CSV data, aggregates it by state and year, and renders the chart using `scaleBand` and `scaleLinear` scales. It includes axes, labels, a legend, and a tooltip that displays the breakdown for each state when hovering.