This chart displays the age distribution of a population across nine South Korean provinces, showing raw counts or percentages of people within ten-year age brackets. A stacked bar chart represents each province, with colored segments corresponding to age ranges. Users can toggle between raw counts and percentage-of-illness views using radio buttons. The visualization uses D3.js version 3.5.6, including the `d3.layout.stack` function for stacking, `d3.svg.axis` for axes, and transitions to animate between the two modes. Data is loaded from a CSV file, and SVG is used for rendering.