As ice floats in water, about 10% of the ice floats above the surface of the water. If we float some ice in a glass of water, what happens to the water level as the ice melts?

My original thought was that the increased water level due tithe displacement of water by the partially submerged ice would be cancelled out by the fact that water expands as it freezes. Basically, I mean that the water level stays the same.

I was wrong though. The water level decreased. I might have used too much ice but I really don't think that would matter.

Anyone's opinion would be helpful.