Where did 0/8 come from?

I only joined VLR this year, and I do not know where 0/8 came from.
Why isn't it 0/10? Did this come from CSGO? From OW?

0/8 nt

OkOkay [#2]

0/8 nt

0/8 terrible reply

0/8 bro you aint fooling me

shit bait 0/8

8 rhymes with bait

Im just as confused as you are man

gr8 b8 m8 i r8 8/8 or some shit

Jokerkid21 [#6]

8 rhymes with bait

gr8 b8 m8 I r8 0/8
yea thats my oldest "memory" of x/8 too

edit: 3 minutes too late looking for the oldest example, see #8 for original "rediscovery"