This choropleth shows U.S. state literacy rates from a CSV dataset, with darker green shades indicating higher percentages and gray for missing data. The visualization uses D3 v7 and TopoJSON to load and render state boundaries via `d3.geoPath` with an Albers USA projection, quantized color encoding with `d3.scaleQuantize` and `schemeGreens`, and tooltips built from `append('title')`. Data is joined by mapping state names to FIPS codes.