BlackStarDeceiver has a point... If your stories don't need a full plot cycle, I could claim every chapter I hit the publish button on in my novel is a published story. Maybe my 21 published chapters in a single novel mean I have published 21 stories like you.
My novel: Frozen at Castle Everest
To answer your question I started 1 story and am hesitant to publish another until it has an ending. I don't think it's helpful to divide your attention too many times.