Understanding This ToolThe context is always the Federal Minimum Wage. In other words, when you first load this page, you will see the real dollar amounts of the Minimum Wage for each year. As you click through the other buttons (poverty line, price of gasoline, etc.), each of those is also a real dollar amount. As you would expect, these values have gone up over the years in varying levels of consistency.
But when you click the toggle button and switch the view to MIN WAGE RATIO, you will be looking at each of those measures in relation to how much that year's minimum wage would buy you. For example, the minimum wage now buys you 25% less gasoline than it would have bought you in 1980. Interestingly, you can buy 6% more eggs on minimum wage now than in 1980.
When looking at Minimum Wage button itself, the MIN WAGE RATIO toggle is showing the official consumer "Buying Power" measure as provided by the Bureau of Labor and Statistics.
Note that each of these charts, no matter the toggle setting, is an indexed value - taking each value and dividing it by the maximum value. This is to make it easy to look at relative growth within a category, not for comparing one category to another (apples and oranges!)
The InterfaceBelow is a visual description for how to read the interface.