This heatmap, while understandable, is lacking a proper legend and the colors are hard to tell apart.

The legend doesn't provide any actual numbers and only communicates that lower rates are darker and vice versa.

It also lacks tooltips so the user can't see proper values, and the overall styling is uneven.

The new heatmap made in D3 is properly scaled, has a clearly defined color scale that is more distinct, and the data is properly sourced and titled.

The legend is correctly and clearly divided, so the viewer can tell what numbers are in what range.

There are also tooltips on each of the squares to display the values and states for each.