If you click
here....I have found a site where someone claims to have purchased a AMICA folding bike which looks very similar to the one in your picture. According to the posting, the bike had a sticker on the seat tube which read 1966. Yours looks like it might be a little more modern, but that could just be because of over all condition.
From the additional research I have done, it appears that these bikes were made in the 1960's. Can't really figure out exactly how old yours is though.