It is hard to say as statistics vary. But here is one showing that majority (58%) of scientists surveyed hold to it over other interpretations.
Elvridge., Jim (2008-01-02). The Universe – Solved!. pp. 35–36. ISBN 978-1-4243-3626-5.OCLC 247614399. "58% believed that the Many Worlds Interpretation (MWI) was true, including Stephen Hawking and Nobel Laureates Murray Gell-Mann and Richard Feynman"