Creating a graphic knowing at which time do we have the 90% of the data

Hi everyone, I'm having some troubles creating a graphic and I would like to know if someone knows how to solve it.

Basically I have a table like the following but with more data:

With that data I created a scatter plot having the different days of the year in the X axis and the hour in the Y axis. I also used the year as a legend and the created visual is the next one:

The problem, is that I also need to know at which hours and at wich days we have the 90% of our data. Does anyone knows how to do it? The correct visual it should look like the following: