De·mon'stra·bly adverb In a demonstrable manner; incontrovertibly; clearly. « Cases that demonstrably concerned the public cause.» Clarendon. Found on http://www.encyclo.co.uk/webster/D/34
demonstrably 1. In an obvious and provable manner. 2. Capable of being demonstrated or proven. 3. Clearly evident, or obvious: 'They had a demonstrable lack of concern for the general welfare of their country.' Found on http://www.wordinfo.info/words/index/info/view_unit/3678/