A bar chart displays the relative frequency of birthdays across the twelve months, with values ranging from 0.04 in February to 0.13 in July and September. The chart uses D3 version 3 to render SVG elements, manually computing bar widths from the dataset length and mapping monthly values to a linear y-axis scale with `d3.scale.linear()`. Data is loaded from a tab-separated file via `d3.tsv`, and each bar is drawn with a rectangle and a white value label, all styled with a steelblue fill.