A line chart shows average annual salary from 2015 to 2035, with a monotone-smoothed trend line and circular markers. Tooltips reveal exact year and salary values on hover. The visualization loads a CSV (or TSV) via `d3.text` and parses it with `d3.csvParse` or `d3.tsvParse`, aggregates records into yearly means using `d3.rollup` and `d3.mean`, and renders axes, grid, and labels through `d3.axisLeft` and `d3.axisBottom`, with `d3.scaleLinear` and `d3.line` for positioning and path generation.