This pie chart visualizes the distribution of operating system users for Android, iOS, and BlackBerry OS. It aggregates data from a CSV file spanning US yearly data from 2009 to 2023. The visualization uses D3 v6 to generate pie slices with percentage labels, a color-coded legend, and a title. The code leverages D3's `pie`, `arc`, `scaleOrdinal`, and `csv` functions, rendering the chart as SVG with bright colors like green, blue, and black.