The idea that "low percentage of admin costs" = "high efficiency" in a non-profit is, well, naive. The resources you devote to making sure the other money you spend is effectively serving your objectives and researching more effective ways to meet your objectives is admin costs -- its trivial to minimize admin costs, but its foolish to mistake minimizing admin costs with increasing efficiency.

Certainly, having an objective measure of value produced and maximizing the ratio of that measure to total dollars spent is a good thing, but "dollars spent less admin costs" is not a good objective measure of value produced for most non-profits.