Passage: The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015.Since 1953 The Astrophysical Journal Supplement Series (ApJS) has been published in conjunction with The Astrophysical Journal, with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume.

Question: At what point was the journal no longer produced in physical copy?
2015