source: https://analytics.usa.gov/

This is the result currently (last 7 days):

 Windows   35.5%
      11   18.5%
      10   16%
       7    0.8%
    2000    0.1%
     8.1  < 0.1%
       8  < 0.1%
 iOS       29.6%
 Android   15.9%
 Macintosh 12.3%
 Linux      5.2%
 Chrome OS  1.4%
 Other    < 0.1%

If we exclude Android and iOS (which make for 29.6 + 15.9 = 45.5%), then the contribution of each of the others would increase (by 100/45.5 = 2.19), leading to 11.388% (5.2 * 2.19).