Since Windows XP How do the different Microsoft OS's compare in % of users ?

This OLD computer I am using still serves its purposes of searching the Internet, email, listening to music from radio stations around the world, watching streaming TV etc.

I chose this desktop over 15 years ago after evaluating several of the leading brands back then. Most other companies touted the speed of this or that but if you looked closely, almost always one of the components lowered the bus speed.

ABS Computers back then offered Personnel, Business, and Gaming computers back then. And I had the ability to mix and match to ensure everything was what I wanted. I lowered the HD size tp maintain the bus speed, I increased the ram to 1 gig (would like to make it 3 gig now, step down one notch in the speakers and changed the monitor from small LCD back then (quality was very poor) to a ViewSonic PF790 19" which has exceptional image and colors still today.
And back then I also received 3 yr parts warranty and lifetime phone support. ABS Computers back then also provided a backup disk and the XP installation disk, while most others had it on the HD.

Now ABS Computers is primarily into gaming, changing components is still there but offers less than half of what it used to.
NewEgg now owns ABS Computers,
Disappointing in that they did not search out past buyers and offer special (better than online) deals to modify the old desktop or purchase a new one.

Sorry for digressing, back to Microsoft and Windows

Luckily back then XP was the OS, the last time I had a used computer windows was pre 98 and was DOS.

In looking back,my question is what Operating System holds the most loyalty and comfort level for its users?
Even though OLD I think many keep XP updated and will switch only when they have to. For me its financail resources,

Vista I am neutral on (neither pro or negative) but leaves a lot to be desired

Windows 7 reminds me of XP, the current Windows 8 RT sounds like a step in my direction
and now with the upcoming Windows 9 curious to see what is improved and what changes.

If I had the finances I would have a desktop, laptop, and notebook, but as it is I would select a home desktop 1st.

My guess is that currently Windows 7 is probably the most used Microsoft Operating System but I wondered where Windows 8, Vista and XP fall into number of current users?

Depending who researches the percentages should vary but in most instances stay close.