S&P 500 Index
This visualization charts the S&P 500 index from 1980 to 2004 using a red area chart overlaid with a black line and circular markers for each data point. The code imports data from a CSV file and uses d3.scaleTime and d3.scaleLinear to map years and prices, with d3.axisBottom and d3.axisLeft generating the axes. SVG paths are created using d3.area and d3.line, while circles are appended to indicate yearly values.