What is the ratio of how often space explorations come out with positive results to the amount of times we try?

A positive result is a matter of opinion. In my opinion, so far there hasn't been any positive result when you consider the billions of dollars spent looking "out there" when the money should have been spent resolving more worldly problems "down here". The knowlege gained in space exploration is far too costly. It hasn't helped mankind achieve anything except satisfy some of our curiosities.