I'm currently on 234 Wins - 222 Losses 51.32%
This. I just got 100/100 more. But otherwise it's the same.
And whenever I check profiles of players on dotabuff.com it's usually looking the same for them as well. Most ppl have 48%-53% winrate as well.
I only once saw a guy with about 62% winrate, but he and his team were really good.
Pro players neither got better stats, I doubt many ever went over 70%.edit:
According to dotabuff my stats: 341 - 326 51.12%
Scratch that above.
http://dotabuff.com/players -> the really good players there are above 500 games tho, those with less are prolly 2nd/3rd accounts