How much material makes up the kuiper belt?

The most accepted range is 0.04 to 0.10 Earth masses; Dr. Stern says up to 1 Earth mass. Back when it was first formed, 4.5+ billion years ago, it had a mass of over 30 Earth masses.

So where did 99% of the mass go? Maybe a passing star disrupted it? Or maybe the small objects were smashed into dust by collisions, and then solar radiation pushed the dust away?

The total mass of the present-day Kuiper Belt is low, in the range of 0.5 to 1 Earth mass. This is known to be too low to have been able to form the KBOs in the age of the solar system. It is therefore surmised that the primordial Kuiper Belt was many (e.g., 50) times) its present day mass.

http://www.plutoportal.net/aboutkuiperbelt.htm

Without looking up anything I have heard that all together it would make a mass about equal to Mars, or slightly over.