why are most people right handed

humans are different from most other animals in this .. most of us (close to 90%) are right handed .. but is there any evolutionary reasoning

humans started using tools very long ago (the oldest stone tools found are 3.5 million years old !!) .. we started sharpening stones to make axes / hunting gears / hammers etc etc .. but such tools would have been a prized commodity to be used by a group or a family .. there would be less tools than users .. most of the tools worked better in one hand than the other (try asking a left handed guy to use your scissor and you would know), which means that it's more efficient for the group as a whole that everyone is better at using the same set of tools with one hand .. now i can't think why right would be preferred over left in evolution so i just assume it was 50:50 odds.. so more and more people became so that they could use the same set of tools which leaves us where we are now..