This example visualizes the distribution of parking data usage years from the RDW open dataset, filtering by the `usageid` and `startdataarea` columns, and aggregating counts per year into a pie chart. It fetches data from the RDW API via `fetch`, filters and maps values with custom functions, then uses `d3.pie`, `d3.arc`, and `d3.scaleOrdinal` with `d3.schemeCategory10` to render the SVG slices. Labels are placed using `arc.centroid`, and the chart displays unique year values as text on each segment. The dataset is retrieved from `opendata.rdw.nl` with a CORS proxy.