This example combines a timeline bar chart with an overlaid line graph to show changes in percentage values across five survey periods from 2005 to 2020. Each green bar spans its corresponding date range, with labels above and hover tooltips revealing exact start and end dates. A green path, generated using `d3.line`, connects the bar midpoints to emphasize the downward trend. Built with React and `d3.scaleTime` and `d3.scaleLinear`, the SVG renders axes, ticks, and bars from the timeperiodv2.json data, with `d3.timeParse` handling date conversion and CSS transitions animating tooltip opacity.