Show scatterplot labels as a % of total rows

[Elizabeth Schuller]

I have a simple 3x3 scatterplot with tiled markers. I can show labels with the row count that fits into each tile. I can also color by row count with the darker colors representing the tiles that have more rows. I would like the labels to show what percent of the total row count the tile represents, and I cannot figure out how. Please help!

See screenshot of my visualization attached.

For example, instead of 42 in the upper left box, I would like to show 3% or 0.03 since that tile represents 42 out of the total 1369 rows in that visualization.