This area chart displays the share of GDP contributed by U.S. school revenue sources from 1890 to 2010, stacking Local, State, and Federal components using a d3.stack() layout. The visualization uses d3.scaleTime and d3.scaleLinear for axes, d3.area() for the stacked layers, and d3.schemeCategory10 for color encoding. Hovering over any layer reveals a tooltip with year, individual source percentages, and total revenue. Data comes from a remote CSV file, rendered as SVG with D3 v7.