Bar Chart Horizontal
This horizontal bar chart displays population estimates for six countries, with each bar’s length scaled to its population value. The chart uses D3 v7 APIs including `scaleLinear`, `scaleBand`, `axisLeft`, and `axisBottom`, with SVG rendering. A bottom axis labels ticks in abbreviated format (e.g., “B” for billions), while horizontal grid lines extend across the plot area. The y-axis labels are country names, and the x-axis is titled “population.” Data is hardcoded as an array of objects, with numeric populations derived by multiplying string values by 1000.