This example demonstrates a dual-axis chart combining bar and line representations. Gray bars show raw counts by year on a steelblue left axis, while a steelblue line with points displays percentage data on a crimson right axis. The visualization uses D3 v4 with SVG rendering, employing `d3.scaleBand` for the categorical x-axis, `d3.scaleLinear` for both y-axes, and `d3.axisBottom`, `d3.axisLeft`, and `d3.axisRight` to generate the axes. Data is loaded from a local CSV file.