This example visualizes the population of nine countries using a bar chart rendered as SVG circles, with country names on the y-axis and population counts on the x-axis. The code loads data from a CSV file and uses D3.js v5.6.0's `d3.select`, `d3.csv`, `d3.scaleLinear`, `d3.scaleBand`, `d3.axisBottom`, and `d3.axisLeft` APIs to construct the chart. It applies custom tick formatting to display population values in billions and uses CSS to style the rectangles and text elements. The visualization is stripped down to a minimal HTML page with a single SVG container.