What we might call that is a graduate of a vocational program in economics, but there is no title equivalent. In the US, titles are not as common as in the Balkans (for example, most would not sign a documet with their title) unless it is MA or PhD, or MBA, DDS, etc and even then only if it is a document related directly to their profession, and only if it is a post graduate title. (There is no title for high school graduate or equivalent). The choice is to leave it off, or to describe it as stated, but to be honest, any title unnecessarily included sounds a bit pretentious in these parts.