2D XY plot with unequal bin widths

I have two variables, x(23520x1) and y (68284x1), that I need to fit using the curve fitting tool. 'y' ranges from 0.02 to 0.07

(Fig: Histo1), while 'x' ranges from 20 to 40. I need to bin the values of y in such a way that the denser regions are in a particular bin while the relatively less dense regions are in a different bin (i.e., bins with unequal widths). I have used 'histcounts' which plotted x and y with equally spaced intervals.

Please help. Thanks!

[Walter Roberson]

histcounts can accept bin edges or bin centers.