The chart doesn't filter values on Zoom. It simply zooms in or out because it is responsive to the volume of data as you will see in the help. If you want to be able to count the items you are looking at you can select by clicking and holding your mouse in either or both axis. That will filter your values and any KPI's you have will then reflect those values, and the dimension you used will show the # of values in the selection bar.
I accept it, Do me a favor, Can you create a scatter on the attached xls. Already the desired output I shared. If Y - Axis in bucket is not possible than make it 0%, 10%, 20% ...... So On. For an idea.
You have too many points to show every point so it shows a Density Map first.
As you begin zooming it will show the number of points in a range, then it will show the actual points. The Axis labels will continue changing as you zoom in. So although it starts at 10% when fully expanded it will shrink to single % numbers when you get more and more zoomed in.