supposedly the RTX2060=GTX1080, so yeah it's a decent improvement.
According to this leak https://www.youtube.com/watch?v=ms7HQ7rckpA
there will be no RTX2060 but rather a GTX 2060 with no enhanced ray tracing capabilities over the GTX 10** series.
It shoulb be around 27% faster than GTX 1060 and around 7% slower than the GTX 1070.
Not certain it's true but looking at the video and regarding recent Nvidia announcements it looks like a pretty solid leak for now.