There is no inclusive definition of "minority-owned startup." The closest measure would be "Companies and organizations owned by entrepreneurs who identify as a minority group member," which was reported to be 22.8% in 2018 by the National Venture Capital Association and.
Unfortunately, there is no more recent data. Nevertheless, it's safe to say that the number of minority-owned startups has increased since 2018, given the rise in awareness of diversity and inclusion initiatives in the startup space.