From Longman Business Dictionary
proficiencypro·fi·cien·cy /prəˈfɪʃənsi/ noun [uncountableU] a high standard of skill in a particular job or knowledge of a particular subjectOne corporation spends $2,000 a quarter bringing its employees up totechnical proficiency.
proficiency inForeign medical graduates must pass a rigorous series of tests, showing proficiency in English.