Original Post — Direct link
about 2 months ago - /u/RubinZoo - Direct link

Originally posted by Bonsparks

I believe Gold 4 is where you stop getting winstreak bonuses, so you actually need to maintain a positive winrate to progress to Plat.

So its decent. Im sure if Riot officially released ranked statistics, its a safe bet that plat is around the top 20-10% of players.

Platinum+ is normally around top 15%.