https://i.imgur.com/9cJ13ue.png (alternative link: https://imgur.com/a/uBG5KUD)

(The area of each circle is proportional to the count, clamped to a minimum value. Axes a are linear.)

Uses the data from https://viewports.fyi/data.csv.

Code:

    import csv
    from math import sqrt
    import sys

    csv_reader = csv.reader(sys.stdin)
    headings = next(csv_reader)
    data = [tuple(map(int, row[:3])) for row in csv_reader]
    max_w = 7100 # max(row[0] for row in data) + fudge
    max_h = 7100 # max(row[1] for row in data) + fudge
    max_count = max(row[2] for row in data)

    margin = 200
    svg_width = max_w + 2*margin
    svg_height = max_h + 2*margin
    max_r = 90
    min_r = 4

    print('<?xml version="1.0"?>')
    print(f'<svg xmlns="http://www.w3.org/2000/svg" width="{svg_width}" height="{svg_height}" viewBox="{-margin} {-margin} {svg_width} {svg_height}">')
    print('<desc>Visualization of viewport sizes from https://viewports.fyi/</desc>')
    print(f'<rect x="{-margin}" y="{-margin}" width="{svg_width}" height="{svg_height}" fill="white"/>')

    print(f'<line x1="0" y1="0" x2="{max_w}" y2="0" stroke="black"/>')
    print(f'<line x1="0" y1="0" x2="0" y2="{max_h}" stroke="black"/>')
    for i in range(0, max_w, 200):
        print(f'<text font-size="64" font-family="sans-serif" x="{i}" y="-30" text-anchor="middle">{i}</text>')
        print(f'<line x1="{i}" y1="0" x2="{i}" y2="-20" stroke="black"/>')
    for i in range(0, max_h, 200):
        print(f'<text font-size="64" font-family="sans-serif" x="-30" y="{i + 20}" text-anchor="end">{i}</text>')
        print(f'<line x1="0" y1="{i}" x2="-20" y2="{i}" stroke="black"/>')

    print('<g fill="blue" stroke="darkblue">')
    for w, h, count in data:
        r = max(min_r, sqrt(count) / sqrt(max_count) * max_r)
        print(f'<circle cx="{w}" cy="{h}" r="{r}"/>')
    print('</g>')
    print('</svg>')