This area chart visualizes mobile phone usage from 2005 to 2015, with the filled blue region emphasizing the upward trend over time. The visualization uses D3 v6 APIs including `area`, `curveBasis`, `scaleTime`, `scaleLinear`, `axisLeft`, and `axisBottom` to render a smooth, filled path within an SVG. Data is loaded from a CSV file via D3’s `csv` function, with years parsed as dates and usage values as numbers. The chart includes labeled axes with tick marks and a rotated y-axis label, all styled via CSS.