The Serbia international became frustrated by a lack of playing time under Roberto Mancini last term and admits he considered leaving City.
However, having made 37 appearances in all competitions so far this season, he is pleased he rejected the chance to move.
Asked if the current campaign has been his most successful in a City shirt, Kolarov told the club's official website: "Until now, yes - I'm sure. I was the same player before, (but) this year I've played a lot more and have shown what I can do.
"Last season I was thinking, because I didn't play a lot, that maybe it was a good thing for me to move.
"I had a couple of opportunities, but in the end I refused everything because I didn't want to go. I hadn't shown the people what I can do.
"Now, this season, I think I have shown what I can do. For me it has been a victory
"If you play regularly you can improve a lot in every game. It is difficult if you play one and then don’t play three, four games.
"Training is one thing, the game is one thing. Playing regularly you can improve a lot."
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