From 25 cents to $7.25, then flat

The message

The federal minimum wage rose in steps for 70 years and has not changed since July 24, 2009. The flat line at the right edge is the point, so the chart runs all the way to 2026 to show how long that line has become.

Why a step chart

The minimum wage doesn't drift. Congress sets a rate, and it stays put until the next change. A normal line chart would draw a slope between 1997 and 2007, implying the wage crept upward in between. It didn't. A step line holds each value flat, then jumps, which is what happened.

Under the line, a pale fill makes the shape easier to read at small sizes. It is the same hue as the line at low strength, so it doesn't add a new color.

Nominal dollars, said out loud

These are the dollar amounts written into law, not adjusted for inflation. A dollar in 1956 bought far more than a dollar today, so this chart says nothing about whether the wage was "worth more" in any period. That is a different and interesting chart (real dollars, adjusted with the CPI), and it would need its own note on method.

Because the unadjusted version can be misread, the axis label says "current dollars" and the subtitle says "nominal dollars." Both are cheap and both are needed: some readers look only at the chart, others only at the text.

Labels for a long series

There are 23 rate changes. Labeling all of them would bury the chart, so only the first rate ($0.25), two milestones ($3.35 and $5.15) and the current rate get labels. The rest stay in the data table below, which is where readers who want every value will look anyway.

Scope

This is the federal floor. Many states and cities set higher minimums, and some workers are covered by different rules. The headline says "federal" for that reason. A map of state minimums would be the natural companion piece.